I would guess that going above and beyond can sit anywhere on that spectrum of boundary crossings, from being harmful to no-one to being harmful to many. I would also guess that many "going above and beyond" incidences are not at either extreme of the spectrum but fall somewhere in the middle.

I for sure know that as a client although I "understand" when the therapist is running late because of an emergency with someone else it does not lessen the harm it causes to me when I am also struggling to "hold on".