Must admit generally if there charging extra for kissing they are normally a shit punt.
Absolutely. I found a WG's willingness to do FK, do it well and for no extra was a litmus test for her general attitude ie not just whether she was enjoying FK but also her job generally, and her willingness to put in the effort for her clients.
If a WG doesn't feel comfortable with FKing clients then that's their choice - they should just be honest by making it clear on their profile they don't offer it and certainly not charging extra for a non service.