In all probability the providers are more concerned about the size of the tip you leave them...and the size of your dick.
If you think that your size is too intimidating for them you could leave just a little bit bigger tip than what is normally given to the providers. If you tip very well you will find out that they will be much more accomodating toward you.
The providers do talk about us hobbyists amongst themselves. I often suspect that they keep some sort of log, or chart, on us. Maybe their memory is better, too...I was at an
AMP on 12/27 and I hadn't seen this particular provider for at least 6 weeks. I tried to tip her 120 but she said "You usually give me 130."...which was true. I figured I could get by for less since I hadn't seen her for a good while.