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....
I agree there is some flexibility here. I always let up on the pin when people tap, but if I don't think they should have tapped I'll ask them if it hurt. I always said tap before
it hurts, but bring it as close to that point as possible.