And don't overlook the possiblity of some kind of scam being attempted. Get a foot in the door, get fired, sue. Happens all the time with injury claims. Probably less likely since "at will" is the employment law in most places, but it's still safer to terminate without alleging any wrongdoing.

Same reason most former employers will only confirm dates of employment on a reference check. They typically won't comment on performance or reasons for termination, just to avoid any potential backwash.