I would crush that skull! It is not like they are delayed at work and missed submitting a move by an hour or two, if all the time per move PLUS all the timebank has run out then you've waited long enough, take your victory and move on 🙂
I suppose rules are rules. Also waited for my opponent to come back, and then for some reason, my pc stopped working for a couple of days - guess what, the b@$t*d timed me out without even a warning!!
Nowadays, I'm waiting with my finger on the mouse for that skull to appear 🙂