Simply because it's openly used everywhere.  Would there be a hundred or more yellow pages ads for "escorts" if it were illegal?  

Nonetheless, it does draw attention to you.  Then again, it's Vegas......probably no big deal!  So I dunno!  LOL

Escorting was outlawed in Clark County, NV in 1992.  But, it is Legal to have a "Totally Nude Dancer" come to your room and entertain you.  My opinion is the law dosen't make sense and is seriously outdated.  The reason is because you don't have to Solicit an undercover to be arrested.  If you walk-in to a "Bust" you are going down with the crowd regardless.

...is legal or illegal? In some cities, an escort is required to register themselves as such and obtain a proper license otherwise they can be issued a citation and be fined; not likely arrested, tho. If this is what you mean...I have no idea . I just thought I'd help get your question back on track if it was. I hope local providers can enlighten you and the rest of us about this. Just using the word 'escort' in an email address would be a pretty weak argument by the authorities that you are, indeed providing escort services.

Symantics

Ill repute is against the law in Clark County.  The word escort itself won't get you busted but it certainly could attract attention if it falls into the wrong hands and LE has nothing better to do that day.

Screen, screen, screen.