diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1dc13afd..1b10be37 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,7 +29,8 @@ this):
   `_setting_int`, `_reset_dwell_on_reentry`, `_next_switch_index`,
   `_spread_weighted_order`, `_odds_color`, `_upcoming_date_and_time_text` under
   the plugins' names and signatures, plus the `_favorite_key` override point.
-  No `__init__` and no state; the host contract is in the module docstring.
+  Constructor-free; keeps lazy state on its host (see the module docstring,
+  which also gives the host contract).
   A new module rather than more methods on `sports_shared`: a plugin that
   deletes a copy and leans on an older module having grown the method fails at
   runtime with `AttributeError`, which no load-time check sees, while a missing
diff --git a/src/common/sports_helpers.py b/src/common/sports_helpers.py
index 53b11482..6ae1c517 100644
--- a/src/common/sports_helpers.py
+++ b/src/common/sports_helpers.py
@@ -187,8 +187,8 @@ def spread_weighted_order(weights: List[int]) -> List[int]:
 class SportsHelpersMixin:
     """The ``SportsCore`` methods identical across the scoreboards' sports.py.
 
-    Stateless and constructor-free; see the module docstring for the host
-    contract and base-order guidance.
+    Constructor-free; keeps lazy state on its host (see the module docstring
+    for that state, the host contract and base-order guidance).
     """
 
     #: Longest gap between two display() calls that still counts as one
@@ -386,7 +386,7 @@ class SportsHelpersMixin:
         if getter is None:
             return (0, 255, 0)
         try:
-            return getter("odds_text", (0, 255, 0))
+            return getter("odds_text", (0, 255, 0))  # pylint: disable=not-callable
         except Exception:
             return (0, 255, 0)
 
diff --git a/test/test_common_is_hardware_free.py b/test/test_common_is_hardware_free.py
index 0b73e939..72cdf512 100644
--- a/test/test_common_is_hardware_free.py
+++ b/test/test_common_is_hardware_free.py
@@ -45,7 +45,7 @@ def test_sports_modules_import_without_hardware():
         for name in {modules!r}:
             importlib.import_module("src.common." + name)
         loaded = sorted(m for m in sys.modules
-                        if m.startswith(("src.display_manager", "src.base_classes")))
+                        if m.startswith({FORBIDDEN!r}))
         print(json.dumps(loaded))
     """)
     result = subprocess.run(
@@ -73,14 +73,23 @@ def _module_level_imports(tree):
                 stack.extend(handler.body)
 
 
-def _targets(node):
+def _targets(node, package="src.common"):
+    """Absolute dotted names an import can load. Relative imports resolve
+    against ``package``, the scanned module's package."""
     if isinstance(node, ast.Import):
         return [alias.name for alias in node.names]
-    if node.module is None:
+    base = node.module
+    if node.level:
+        parts = package.split(".")
+        if node.level > len(parts):
+            return []   # beyond the top-level package; Python rejects it too
+        anchor = ".".join(parts[:len(parts) - node.level + 1])
+        base = f"{anchor}.{node.module}" if node.module else anchor
+    if base is None:
         return []
-    if node.module == "src":
-        return [f"src.{alias.name}" for alias in node.names]
-    return [node.module]
+    # `from pkg import name` may load the submodule pkg.name.
+    return [base] + [f"{base}.{alias.name}" for alias in node.names
+                     if alias.name != "*"]
 
 
 def _violations():
@@ -88,7 +97,7 @@ def _violations():
     for path in sorted(COMMON.glob("*.py")):
         tree = ast.parse(path.read_text(encoding="utf-8"), filename=str(path))
         for node in _module_level_imports(tree):
-            for target in _targets(node):
+            for target in _targets(node, "src.common"):
                 if target == FORBIDDEN or any(
                         target == f or target.startswith(f + ".") for f in FORBIDDEN):
                     found.setdefault(path.name, []).append(f"line {node.lineno}: {target}")
@@ -120,5 +129,35 @@ def test_the_scan_sees_a_direct_import(tmp_path):
         def later():
             from src.display_manager import DisplayManager
     """))
-    targets = sorted(t for n in _module_level_imports(tree) for t in _targets(n))
-    assert targets == ["src.base_classes.sports", "src.display_manager", "src.plugin_system"]
+    targets = {t for n in _module_level_imports(tree) for t in _targets(n)}
+    assert {"src.base_classes.sports", "src.display_manager",
+            "src.plugin_system"} <= targets
+
+
+def test_the_scan_resolves_relative_imports():
+    # A module in src/common reaches src.plugin_system through `..`.
+    tree = ast.parse(textwrap.dedent("""
+        from .. import plugin_system
+        from ..plugin_system import plugin_manager
+        from . import sports_shared
+    """))
+    targets = {t for n in _module_level_imports(tree)
+               for t in _targets(n, "src.common")}
+    assert {"src.plugin_system", "src.plugin_system.plugin_manager",
+            "src.common.sports_shared"} <= targets
+    # The package decides where `..` points.
+    node = ast.parse("from .. import plugin_system").body[0]
+    assert _targets(node, "src.common") == ["src", "src.plugin_system"]
+    assert _targets(node, "a.b") == ["a", "a.plugin_system"]
+
+
+def test_the_scan_flags_relative_imports_in_src_common(monkeypatch, tmp_path):
+    # End to end through _violations(): both relative forms are reported.
+    (tmp_path / "bad.py").write_text(
+        "from .. import plugin_system\nfrom ..plugin_system import x\n",
+        encoding="utf-8")
+    monkeypatch.setitem(globals(), "COMMON", tmp_path)
+    found = {name: sorted(hits) for name, hits in _violations().items()}
+    assert found == {"bad.py": ["line 1: src.plugin_system",
+                                "line 2: src.plugin_system",
+                                "line 2: src.plugin_system.x"]}
diff --git a/test/test_sports_helpers.py b/test/test_sports_helpers.py
index 3bfe2aab..f2ef99a6 100644
--- a/test/test_sports_helpers.py
+++ b/test/test_sports_helpers.py
@@ -8,8 +8,9 @@ loses those tests with it.
 The parity class is what keeps "byte-identical" true after this lands. Point
 LEDMATRIX_PLUGINS at a ledmatrix-plugins checkout and every promoted body is
 compared, as a docstring-stripped AST, against every plugin copy that carries
-it. Without the variable it skips rather than fails, since CI has no plugins
-checkout.
+it. Without the variable it skips rather than fails, since core CI has no
+plugins checkout; ledmatrix-plugins CI runs the same comparison against core
+(scripts/check_sports_helpers_parity.py, ledmatrix-plugins#495).
 """
 
 import ast
@@ -505,7 +506,9 @@ def _plugins_root():
     raw = os.environ.get("LEDMATRIX_PLUGINS")
     if not raw:
         pytest.skip("set LEDMATRIX_PLUGINS to a ledmatrix-plugins checkout to "
-                    "compare sports_helpers against the plugin copies")
+                    "compare sports_helpers against the plugin copies; in CI "
+                    "this parity check runs in ledmatrix-plugins "
+                    "scripts/check_sports_helpers_parity.py (#495)")
     root = Path(raw)
     if (root / "plugins").is_dir():
         root = root / "plugins"