Yes, he can either have a program which deleted files which haven't been requested in a while or he can delete or when his storage is getting full, or not at all. It's all very easily controllable for him, and he has plenty of advance warning.
The bandwith issue is slightly different. If for example some people used his picture storage area to hot link images on an adult page and he didn't check for a few days, then some of those adult sites can get 100,000's or even millions of hits a day. He may find that the bandwith he has paid for a month is used up in a few days. Then he gets an email from his provider telling him he must pay another $50 or whatever for excessive usage or they will cut off his account for the rest of the month or even terminate his account. And all because he was doing us a favour.
That's an extreme example, but it can happen, so we must be good boys and girls
