A Question about Dealing with Access Disputes

I have a question about how we deal with access disputes.  Not about the legal aspect of it but the social implications, the ethics of it all.  Let me see if I can explain this correctly. What do you do - or what should we do - when faced with an access dispute when we are with another person and it's sort of their event?

For example, what if you are accompanying your mother to an appointment with her doctor and someone at the doctor's office says you can't bring your SD in? Do you handle it the same way you would if you were going to your own doctor's appointment, or do you let your mother handle it since it's her doctor, or do you stop and ask her how she'd like you to handle it?

Or what if you are going with a friend to get her hair done and someone at the hair dresser's says you can't bring your SD in? Do you handle it the same way you would if you were going to get your hair done, or do you let your friend handle it, or do you ask her what she'd like you to do?

Or what if it is your friend's birthday and you are going out to dinner with him and some other friends and you are denied access at the restaurant? Or... you probably get the idea. In situations like these, do you just deal with the access dispute as you normally would? Do you feel it's the other person's responsibility or place to deal with it? Do you deal with it together?

And if you were in the place of the mother or the friend, and the person accompanying you experienced an access issue, how would you want it to be dealt with?

I don't know the answer.  I'm curious about what others would say.