Yes being an escort is legal but soliciting is illegal. Soliciting would include talking about sex, discuss pre terms and abbreviations before hand and placing these in your ads.
Even GFE could be misinterpreted as soliciting for sex. I am new but I have done some homework. This is in CAnada by the way.
Additional Comments:
Going back the the earliest post, I think GFE means an intimate encounter. That is just me and I guess we all have different points of view. I guess I just assumed that the general public even the hobbyist were being safe considering what is out there. ;)