They are supposed to. Their behavior is a little unsavory in my opinion They are a member of the Council of Graduate Schools. They contacted me about ten days after the application deadline passed with the acceptance and financial assistance hoping to lock me up right away. Unfortunately, they weren't my number one choice. It's a great college town, but they aren't known for their mathematics and it's also not a really good location in terms of potential job prospects. I kind of have a feeling they are bluffing with this deadline hoping to put pressure on me to accept. I simply won't accept unless I hear back from other schools before their earlier deadline, but it kind of sucks to know they are threatening to remove the offer from the table.
I have yet to year back from my top choice yet.