At check-in many hotels aks to presigne a blank-credit-card-"paper".

And practically always I do so (and till now I didn't have bad experiences I have to admit).

But I know that I shouldn't. (Even more as my European Credits Cards don't allow officially to cancel charges the next 30 days as the US-cards do).

And may be I should also automatically know (it is somehow embarrassing for me, I am soooo shy, to ask the hotel-employee) how much they "reserve" as approval-amount from the credit-card-company, as some credit-cards have a limit.

Any body who handles this situation better, and in a more secure way, than I do?