I believe you're talking about the sort of situation where, e.g., you start to put your hands in a position to do something, and they tap before you actually put any pressure on at all. I just think it doesn't change the question. They do have the right to ask you to let go of them before you do anything, to not put a joint lock on them at all, etc, even if you are in no way hurting them or even really doing anything. Of course there are many ways, (both verbal and non verbal), to convince them to change their mind, and some of these 'conversations' can happen quickly with body language, where you can 'ask' in a non verbal way and they can 'agree' in a non verbal way, but you both understand each other and agree so it's fine.
Thanks for that reply. I can assure you if the tapping out is a 'let go' communication then I let go.
I think you'll find in the example of nikkyo the communication is not 'let go' in fact it's more of a panick reaction.
Anyway, I'll now add a bit of history just for your amusement rather than for debate. How I was taught. Not however how I teach. Old school I'd call it.
When doing so called warm ups in the advanced classes we would be doing things continuously for at least half an hour. Aikitaiso would be done according to what he called out in number ie: Backward ukemi ten, followed by ten, followed by twenty, followed by foreward ukemi ten etc. etc. non stop. Continuous foreward ukemis around the mat from kness and backward too. Now his rules were different. He would walk around with his little stick. If you floundered, whack. If you complained bigger wack. If you tapped out through exhaustion whack. His rule was 'you've had enough when I say you have'
Strange as it may seem we liked it and it took us to getting through barriers we were sure we couldn't. No one ever got injured this way either. A few red patches ha,ha.
Meanwhile when it came to pins if you complained he'd do it more. If you whelped or said anything at all in any manner he'd do it more. His rules here were but two. If you tap out early you're gonna feel pain. If you use your mouth in any way your gonna feel extreme pain. On the other side of the coin was if you tap out when you are certain it's 'on' and you are correct AND you tap out in complete silence he would immediately let go and tell you well done.
Once again shock, horror, he overrode ukes determinism as standard procedure. Once again he always seemed to know how far he could go as no one ever got up injured. Once again a different set of lessons learned. Once again we all enjoyed it too. Well, the five of us who survived that class as three said not for them thank you very much.
I don't know how close that type of training is to old school Japanese training but we were led to believe so. It was almost a cardinal sin and sign of complete and utter weakness to even murmur if you felt pain yet it was also a cardinal sin not to let go if the person tapped without any sound coming from their mouth.
Just a little window into the past or rather my past. Funny thing is they are still fond memories.