If the exchange runs some type of business, then that's where the people are headed. For users with small-scale and regular deposits, of course, they will consider transfer fees as a loss, so they try to be as efficient as possible to do that.

This change of funding address is indeed very rare. Luckily, aside from announcements, binance has an effective tactic of manually reflecting balances by support so that users are aware at a moment's notice that the funding address has changed.