For me, if it's possible to get the response I want then I'll keep trying for it.
If hugs were given under special circumstances, I'd keep trying to make those circumstances happen instead of focusing on trying to get better.

Intermittent reinforcement keeps the behavior continuing a lot longer than continuous reinforcement. Getting the response you want but only rarely and unpredictably reinforces a behavior a lot more than getting it every time or not at all. That's why people get addicted to gambling.
That's why I don't want my T making exceptions. Obviously some flexibility is necessary and it varies by person and situation, but it's something I warned my T about early on because I know myself.