If an operation is fallible, it should return an error type and make it the job of the caller to deal with that. Silently returning default seems like a disaster waiting to happen, ala On Error Resume Next (which indeed was a disaster to deal with).
Now if this panic handler, instead of silently continuing in release mode, invoked some sort of "save your work and restart" handler such that the user doesn't lose anything and the program would restart in a known-good state, that seems like it would be a sensible way of doing things.