If there's nothing on the provider's profile or reviews indicating she likes alcoholic beverages, be sure to ask before bringing something. Something like, "I'd like to bring a beverage to share with you when we meet, what's your favorite?" A couple of my favorite providers don't drink alcohol. One's a "health nut", so she favors teas and smoothies, the other is on some meds that don't mix with alcohol.

Some gals refuse alcohol for what ever reasons (might just be a recovering alcoholic!)  I'm sure none of us would choose to undermine someone's recovery.    Personally I can't afford the calories.      
Some providers have offered me beverages with or without alcohol...  I've had gals who had an alcoholic drink for themselves & those who did not.  Never had a gal that seemed under the influence but would walk out on one that was.  
I usually stick to water or an herbal tea.    

Reminder:  any beverage you bring in, should be sealed so there's no question of tampering.

I hadn't thought but can only imagine a person in recovery...  goes in for a kiss we very much want...  only to taste alcohol.  My demon is sweet treats & a single taste kicks me off my diet.  Not the same, I know, but cravings are cravings.

Providers vary on this greatly.

Some don't want anything alcohol to drink, some don't want YOU to drink.  

Vast majority don't want you to show up drunk but most are cool drinking together. Keyword here is "together"... not "before".  

I try to keep my drinking to at most 1 or 2 drinks before getting started because I don't want to end up unable to perform.  

I've had some providers who kept offering more drinks and really wanted to party. Some got so drunk they blew chunks.  

Fortunately, all the chunk blowing happened off the clock and not during a paid session