The third bullet in 7.2.1 says:

[A Media Overlay Document] SHOULD use semantic markup where appropriate.

Aside from this being overly vague, I can't find anywhere where semantics could be applied where they are recommended. The skippability and escapability sections don't recommend semantics be set, and these would be the key reasons for them.

Should we remove this statement and determine in the future whether to recommend semantics be set for skippability and escapability, or even leave this for the accessibility specification to require? (It also only has semantics as an optional requirement right now.)