I've had two instead of one. Don't remember which hotel.
I've had a hotel pre-authorise for the price of the stay ( on a pre-paid stay).
I've had hotels pre-authorise big amounts of money ( depends on lenght of stay/amount of rooms/fanciness of hotel).
But all pre-authorisations (e-checkin/ desk checkin) dissappear after a month automatically so I wasn't worried.
And they dissappear sooner if there is anything to bill you for.