Monro Muffler Brake

My wife brought a trailer tire in for a patch only. It had a screw in it. At no time was she informed that the tire was going to be balanced as well as patched. I have never had any trailer tires balanced. Had she been informed this was going to be done and charged I would have her taken it somewhere else or requested that it not be done. When she picked the tire up and paid for it, I noticed on the receipt I was charged for the balancing. I immediately called the shop where I was given an explanation that it's standard to balance the tire. Shouldn't that be disclosed when dropping the tire off if it's going to be charged?