On those rare occasions when someone hasn't respected my tap, my first instinct has been to get off the ground as fast as I can (once they let go) and punch them in the face. I haven't actually done it, but is that really the kind of energy you want in someone who's going to be torquing on *your* arm in a few minutes?
I'm lending you my body for your practice. As with any borrowed property, treating it as if it were your own is the *minimum* standard for behavior.
See. I tell a story about something that happened about 10 years ago and look what happens.
On those rare occasions I've been teaching, or when I talk with people about safety in the dojo, I remind people that we take turns and if someone gets out of line and over-torques a pin, or continues to stretch after the submission, guess what - the other person gets a turn, too... If nothing else, that's kept things civilized. I frequently ask to be stretched gently after a "first tap" - as in - please hold it there for a moment, I'll push against it for a few seconds and then can you apply a little more stretch - and then I'll tap again, expecting to be let go. That, however, happens after we've talked about getting a bit more stretching....