Nice to see the good folks of the community standing up for the rights of models. I think the notion of paying a model for a session is just a structured way of allowing her to have the fun she wants, without having to fear of putting herself under undue financial stress.
These models aren't your girls LITERALLY next door. They have to travel, sometimes on tours, so that they can make ends meet for themselves and still manage a life outside of this work. How could you not feel a sense of obligation to offer fair compensation? The effort of having to find clients, arrange times for sessions, the travel, room and board...not to mention in many cases, these are freelance workers who don't get the benefits involved with your regular 9-5.
Models who cater to the tickling fetish (most times) are offering it because they DO like (enjoy, love, curiously entertain...who cares?!) it. Whatever their reasons, it should be respected. Otherwise, you don't HAVE to hire them.
If it weren't for models, there would arguably be a lot more anger and misogyny directed at women from frustrated men who lack the manners to find someone who will indulge them. It's bad enough as it is now.