Having worked in retail and also as a freelancer, I stand by not ever using this policy. While working in retail, time and time again I was cussed at, spat at, belittled, and when I ran to my managers for help, they would give the customer everything they wanted and then some, in front of me, and I received smug "victory" glares from the unruly customer. It made my time there absolutely /miserable/ and hate my bosses more and more to the point where I didn't even care who they were going to have to beg to replace me if I called in sick to work. If they treated me better, I would probably have felt guiltier about them being a man short.
In the freelance world, I refuse to take shit from /anybody/. I /will/ cancel your commission if you're an unruly asshole to me. I love money, yes, and certainly like everybody else I need it, but honestly you couldn't pay me enough to accept the kind of abuse I've gotten. Hell, I once even canceled a commission outright, no excuses, hands down, because the commissioner was treating my /boyfriend/ like absolute shit, and had the nerve to call me unprofessional because I was letting personal matters affect my business relationships. ;)
I encourage artists to not take shit from anyone, and if you work in a job where your managers are constantly making you look like the jerk in front of the customers, I suggest printing out this article and pinning it to their office door ala Martin Luther.