Let's say you meet Provider A, have a great time with her, and tell her want to see her again. You don't have the chance to hobby often, but you send her a short e-mail or PM every now and then to remind her that you're still alive and interested.
The next time you have a chance to hobby, Provider A isn't available. So you call Provider B, have a great time with her, tell her you want to see her again, and send her a PM or e-mail to say "Thanks, let's do it again soon."
A potential problem arises when Provider A and Provider B know each other -- maybe they're friends; maybe they share working quarters.
I know it's a business, that what's a special experience for me is an everyday occurrence for the ladies, and that they're blowing smoke up my ass when they say they had a good time and want to see me again soon. However, as Ragnar put it succinctly in Rule No. 3: "These ladies are a lot more sensitive than you think they are." And even if they're not sensitive to the fact that you're fucking someone they know after you've told them how great they were and how you wanted to see them again, they might be a little angry or jealous that some money that could have been theirs is going to someone they know.
I suppose I could broaden the question to include Provider A reading a review of a session with Provider C, whom she doesn't know. The complicating factor of the two knowing each other isn't present, but the potential for an "adverse sensitive reaction" still is.
I suppose this might more of a concern for the GFE-seekers rather than BnGers ... f it's a concern at all.
Legitimate concern, overthinking it, or "just shut up and fuck"?