at hotel room. scrutinize always. probably safe in incall but be careful if in small town, safr in big cities

by their review history, their presence on local boards, or first hand recomendations from other hobbyists or providers whom you trust.

Anything else is a bit of a gamble.

Are more difficlt for me to set up with...  must be able to jump when they are available.  Perhaps I am prejudice because I favorite potential Favorites & that is harder to do with touring providers.  just saying.
Touring providers may not know the area or have transportation, so may be less discreet.  MUST generate a higher traffic voltume to pay costs which again works against discretion.  
Touring providers are more likely to step on the toes or invade the "turf" of some local (who may in turn drop a dime on the visitor).  

IMHO, you just need to do your homework throughly.  
skb

LE's true primary concern is what the public can see.  That would be streetwalkers first and CL/BP next. Girls who are "known" to LE are mostly low-end providers and not the gals you want to be seeing in the first place. A discreet provider who knows the ropes is as safe as you can get regardless of whether she is local or traveling.

If anything a provider visiting a new city for the first time can make some serious mistakes simply based on not knowing the lay of the land.  I saw a new lady last month who had booked herself into one of the most provider-unfriendly hotels in town. I almost canceled the appointment when she told me where she was staying...