which hotel is it ?
Online checkin is requiring a pre-authorization. Or you don't do the online checkin, the room will be ready anyway and they have to give you the voucher for the drink at the same time as the card so you may check directly which amount could be blocked upon checkin instead of 1K with online checkin.
It is supposed to be covering minibar, breakfasts if you didn't take them as first, room service... but still, 1K is a lot.