American Express has been doing this to most all of their customers for the past few months. Its been in the national news and in the newspapers.
If I am correct they are attempting to get do just banking and drop their credit card department completely. So to do this they want to get as much money as soon as possible. And it seems to work because people will pay more on their balances now to keep the over the limit fees from being applied. So actually more money is being sent to American Express.

I do feel badly for anyone who has credit cards and cannot pay the balance off. Its only going to get worse instead of better.