Check if std::move is done on container

Is there any way I can check is std::move done on some STL container?

I have two types of classes (lets say A and B), they keep (some) instances of another class in their internal container. If instance of A keeps instance of B in it's container, that instance of B have to keep the same instance of A in it's container, too.

A can see B's private methods (B has it as it's friend), but I have to implement move constructor on B. As B can see both's internal container, I've implemented B does all adding and removing for both classes.

Problem is:

I have to implement move constructor for A, and use stl::move on that container. After container is moved to new instance of an A, only way to notify B of detachment of old class is through the method that uses B's, and old A's container and does removing for both of classes.

Is there any way for B to know that old A's container is moved and it shouldn't acces it?

It works without checking, but as class doesn't have defined state after std::move, I shouldn't call ::remove() on it (professor says it's an error).

Please note: this is my homework problem, so I wouldn't like to get illegal help of solving complete problem, only the part of checking of object's consistency to skip calling it's functions after moving it.