How about `find_events(raw, onset=True, offset=False)` for what we currently have, either `find_events(raw, onset=False, offset=True` or `find_events(raw, onset=True, offset=True)` for what @dengemann wants (depending on the use case), and `find_events(onset='include-nonzero', offsets=False)` for what @simonster wants? This mirrors how we use `True` versus `mag`/`grad` for `pick_types`, and I think it covers all possible combinations one could want while still being simple.