Usually, there is an amount of supplies that "feels" right. Less, and the job is not going to get done properly. More, and it gets wasted. Where I work, I find the "sweet spot" to be 3 shots of soap (though that can be more or less, if they get a different type of dispenser--it used to be 2 shots when they had a more concentrated soap) and 4 lengths of towels. These things are small on purpose--otherwise, small children would waste more than half the towel because their hands are much smaller. More than those quantities simply do no additional good.
But, if they are going to be posting crap like that, I would just go ahead and waste supplies out of spite. I would use more like 3 or 4 ounces of soap, not shots (they are usually about 1/2 milliliters per shot of concentrated soap or about 1 tablespoon of foam per shot). I would also like to take the whole roll and stuff it in the toilet--at that, one of those monster commercial size rolls. Now that ought to waste a good deal of money.
