As I mentioned earlier, this is new. It used to be that after you checked into the hotel, your free play would be uploaded onto your card. Unfortunately, there were occasions where this didn't happen, and supervisors had to email corporate, yada, yada, yada. So now they've put the free play into the kiosk for guests to download themselves.
I have no idea, though, why yours didn't seem to require a hotel check-in. Maybe a mistake in your favor?
I've always said that everybody -- locals and non-locals -- should check "Today's Offers" in the kiosk when entering a Station casino. You never know what might show up there.