Adding to this subject that seems to be getting OT from the thread. Indeed places do look for an authorization/pre authorization for more than the amount, such as restaurants, hotels, etc. It is not an actual charge, just a pre auth.

This is the reason you see signs at a hotel stating that if you use your check card at check-in, it may tie up some of your funds for a few days.

This is also done at "pay at the pump" fuel pumps. This is what prevents someone from swiping a visa gift card for instance, that has $25 on it, then filling up their tank for $50.