I don’t understand why credit cards are secured so badly in the states. Here you can’t adjust a charge after it has been confirmed (plus you usually have to enter a pin whan swiping the card if the amount is over a certain threshold).
Kind of related: when my family went to the US for vacation and we ate at some restaurant, the waitress came with the bill, my dad said something like “make it $x”. When she sait to just write in the tip on the bill and my dad told her that won’t work she insisted that thats how it always works (which tbf it probably does for american customers). Sure enough when we checked the card statement later on they just took out the original amount, not the tip writen in.