Also, at the time of booking you only have to pay the deposit (10% I think) and then you can pay the rest when you check in. I did this when my family visited me. I paid the deposit with the booking and then when we checked in, they paid the remainder of the fee.
As far as going in early to show your ID goes, the CM only has to go in early if they're not staying with you at the hotel. If they are, they can just show their ID when you check in.