I don't think anyone here has a problem with your statement that uke shouldn't tap out of anticipation of what might happen. That is poor training practice, and among other things it prevents tori from practicing effectively.
I think what Janet and Katherine have taken issue with is that tori is expected to know the difference between a jammed toe and anticipation. It is easy to assume one when it is really the other, and as such a tap should always be respected.
IMHO, if you are having problems with someone anticipating, have a quiet word to them and obtain their consent to slowly apply the lock to a point beyond that which they find comfortable and progress your training from there.
Robin. I never mentioned jammed toes or anything like that but merely the point you say no one had issues with.
It no doubt can be difficult to notice the difference between that and a real situation but that doesn't mean you can't and also that you can get very good at it. In my view a teacher should be very, very good at it.
I have no problem with it myself but see many who do.
A phenomena I would say many teachers know about and know the difference.