diff --git a/docs/SPEC.md b/docs/SPEC.md
index 5123d6b..8a6da1b 100644
--- a/docs/SPEC.md
+++ b/docs/SPEC.md
@@ -997,8 +997,10 @@ rewritten.
 
 **Media shorter than 120 s.** The window `runtime/2 ± 60 s` underflows, so no
 signature is emitted and **no sync offset is applied**. Such items fall back to
-the runtime/exact tiers, which is adequate: a 90-second extra or trailer is not
-the content whose cut alignment matters. Both producers must apply the identical
+the runtime tier, which is adequate: a 90-second extra or trailer is not the
+content whose cut alignment matters. (There is no `exact` tier: the file-hash
+tier was withdrawn on legal grounds — it fingerprinted an individual copy rather
+than the cut the timings describe. See the server spec §3.) Both producers must apply the identical
 rule, or they diverge on exactly the short items most likely to be
 mis-identified.