I have chosen to eventually ignore a couple of posters here that seem to rejoice cutting and pasting excerpts from the PRA and then repeating them ad nauseum as if they think repeatedly ramming it down everyone's throat will make it so in regards the use of dental dams.
The fact remains that generally sexual services advertising is non specific and can be open to interpretation and application in regards mutual oral services (and other services like GFE, DFK, VIP, PSE etc). I struggle to recall where specific mention is made in the advertisement for a requirement for dams to be used. This includes advertising that specifically state protected services at all times, and in the same add mutual oral is a listed service.
When meeting the WG the accepted norm (law) is protected penetrative sex, absolutely no arguments here. But in my experience cunnilingus where it is offered as a service has always been offered as unprotected. Dental dams have never been required let alone mentioned. That is the overwhelming norm, no matter how strident the other posters are that it is not, or that it should not be. And saying something over and over again does not make it so.
