most quality providers would prefer that you show up sober.  At the same time, many like it if you bring one of their fave beverages.

Swim

Yes, but it depends.

Most providers will be offended that you show up somewhat tipsy, but are coherent. First impressions are important, and you may lose their respect for that. In return, they may feel uncomfortable being with you, and you cannot use them for references if the experience was not pleasant.

The only time that I had some drinks was when I booked multiple hours with providers, and they suggested it. In one occasion, we went out and had dinner and I had about 3 drinks within an hour. In another occasion, the provider suggested that I bring her favorite vodka because it was a two hour session.

I would think it would be rude though to show up and was a bit tipsy, its kinda disrespectful IMO. First impressions are very important, so please keep that in mind.

save the drinks for after you have seen a provider.Do not show up reeking as alcohol and tipsy that is a turn-off.Having a drink with a provider is one thing showing up already almost two sheets to the wind is not cool.Plus sometimes alcohol affects below the belt you definitely do not want to be in that situation.
Show up sober for your appointment clean smelling breath that does not smell of alcohol.
Keep happy hour on your own time!lol
Just my .02

Are you coming directly from a previous engagement or nervous about your visit? It does seem a bit rude and/or disrespectful. It would seem more inline to ask the provider if you can share a drink during the session or at dinner beforehand - whatever your plan might be

Have fun & play safe!

Summer

Won't cum as fast! Is that your ploy to getting all you can from your provider? Shame on you! Drunk people don't know that people that aren't drunk know that you're drunk no matter how smooth you think you are at covering it up! So a tipsy appointment is no way to go, if that's the case, stay at the bar where you're drinking at, find the first passed out/puking chick and screw her silly for FREE! She won't remember if you're good or not and you won't be too embarrass if you do something stupid thinking it's sexy! LOL!

What if SHE showed up smelling of alcohol and tipsy? "Do unton others as you would have them do unto you"

I dont know,I work long days and live in hotels
and usually will have a couple beers after work,
and have never had a provider who had a problem with that.
have had a couple girls ask if they could have a beer.
being drunk,or tippsy is  probably not a good idea,from some of the stories
I heard from a few providers,they have run into some sketchey people
and you are just gona scare her being that way.