I was thinking you do a hacking minigame with arrows to put it on the machine within a certain time, if you take too long the machine blows up and sets off an alarm and gives you a wanted level. If you succeed then I guess the skimmer would only be good for one use??? but then what is the point, and do we create money out of nowhere or let you steal the victims money? how much do we let you steal? do we give a wanted level or tell people that you skimmed the atm??
Maybe you can 'check' the atm for a skimmer before you use it but also requires a minigame pressing the arrows? ppl might forget or be lazy and take the chance they could lose a bit of money