Amex to pay people off to close accounts?

It seems like a good deal for both company and customer. Amex gets to unload some deadbeats and get their money back minus $300 bonus, while the deadbeats get their hands on $300 they wouldn't have had otherwise. The big problem I see here is that a lot of people, especially now, really would like to pay off their credit card balances but CAN'T. So an incentive isn't really going to make these people pay up. I don't have an American Express card, but have never run up big balances on my credit cards...I've always used them as a form of convenient payments and to get rewards so I'd consider paying interest on my balance to be me not using them right! So I wouldn't have gotten an offer. I'd have taken it if I did get it, though. It's hard to pass up $300 in free money, and there are other credit card companies.

I've heard of this thing about Amex, so if you received the letter from them, is it a MUST that you pay off the balance and receive the $300 or it is an option that you can reject or accept?