Oh, it’s petty cash to be sure. If you have $100-ish bucks to throw around, you probably aren’t going to miss much by not doing this. Unless, of course, letting someone else take even one dollar from you in this way is against your religion or something (i.e. the principle of the thing). Conversely, if you need the handful of dollars this makes, you probably don’t have that kind of walking-around money in the first place.