[lotsofpulp]

It depends on your clientele. If you're in an area where everyone is well behaved, then you might be right.

If you're in a place with tons of mentally disabled folk or other type of people that don't respect public areas, then it's going to cost you more than it helps you.

Also, it could be more headache than its worth if you're at a big tourist spot where the probability of someone buying something is not high enough compared to the enormous amount of people who will want to use a bathroom.