Animation Override notifications

Is there a way to detect when a clip starts playing in an timeline (on the animation override track), I now I could use signals to detect it, but it could be error prone / forgetful for the designers, so I'm just looking for a way to automate it.
i.e:
We have a timeline with duration 10sec, on 4th second, a 3 second clip starts playing. So I'd like to get notification/callback/whatever at 4 and 7.

I could also check tracks, pull animation track, pull clips from it and just do simple time position comparison, since clips contain start & duration values.

Any other way?

Thanks,
Marko