The main problem here is not that tickling is lewd, or sexual in every case; it's that money changes hands. Once that's happened the lewdness is up to the discretion of the establishment. In America there is a lot of power in the hands of fundementalist, right-wing Christians who disapprove of anything and everything that doesn't involve a man, a woman, marriage in the sight of Christ and no other heathen bastard deity........ and the missionary position.
In Iowa some poor bastard got found guilty of Statutory Rape because he dared to have sex with his girlfriend. He was 31, she was 29. The crime was that they weren't married, so the religious right who controlled those particular laws (which hadn't been updated since Iowa was first settled as a territoty most likely) shafted him well and truly. Since his release from a 5 year prison sentence he can't even be allowed to see his poor, distraught girlfriend, because the law there views her as a victim, and placed an automatic restrainment order on him.
Another state (I think it might have been Georgia, but I'm not certain) had a guy imprisoned because he commiteed the heinous sin of receiving oral sex from his wife. (Not girlfriend, but WIFE!)
While laws like this exist and are not changed or updated (there's probably one somewhere that explicitly states what a chastity belt should be made from) I'd feel nervous about even attending a gathering!
*DISCLAIMER* This probably goes without saying, but I'll say it anyway. I mean no offence to anyone who describes themselves as a Chistian. The only people I am pissed off at are those so full of self-righteous indignation that no other emotion can exist in their body and who feel it their God given duty to make sure everyone else in the country is equally puritanical. (Forcible burning at the stake if proven intransigent.)