When does the "caught" tag apply?

In the context of a series of images as time progresses.
Would it apply when one or more other(s) notice the character, or would it apply when the character finds out they've been caught by the other(s)?
For example: character1 is doing something lewd, character2 sees them but doesn't speak up until they're finished.
And what about after? Say there's a couple more images showing dialog between the two. Would it be added to those images?
Thanks!

I think it should apply in a set of images where the act is "witnessed" and continue to apply until the act is no longer relevant. I.e, the perpetrator(s) and the witness(es) moved on from that moment and are partaking in different actions now.
post #2357689 (NSFW) is an example where the actions are witnessed, and "caught" applies throughout.