That's why I leave cash instead of card when I use hotels in SD, in case they insist on guarantee. With cash you get a receipt and they have to give it back to you (I don't use minibars or phones - have my cellular open plan).
Whenever possible, I ask for minibar be closed and phone be shut down, so no deposit is required. But sometimes they insist...that's when cash comes in... I tell them my card is Dominican Debit card and any amount authorized immediately becomes charge (they know that it's the case with Dominican debit cards, so they accept the excuse).
But sometimes they insist on a card (I try not to stay in those hotels - e.g. Barcelo Lina) and say they will only "enter it into the system" or pass it through the "iron" (that's what I call the manul imprinter) and get you sign the blank slip ...
... I found a trick for this one as well ... Because when they say they only imprint the card and do not put actual transaction on it, I had a friend of mine get me couple of those US$200 gift cards (blank card, no money loaded) that hang around in abundant quantities in wallmat, cvs, etc. So these guys can now be imprinting "that" card all they want, and can even clone it if they wish so.