In sequencer it’s not uncommon to have links break as changes are made.
Actors names in Sequencer turn red when this happens so it’s easy to spot the problem and remedy by re-assigning or using the fix option.
However the attach and path tracks do not. (I already filed a feature request)
The Camera cuts also does not indicate that it’s has an unresolved camera. The user has to click on it → Properties and check Camera Bindings
Red text or other indicator (warning symbol) would be handy as this becomes baffling to users as the camera view is fine but rendering or playback shows a random view.