Ive seen a couple players who drink on the changeovers, I never want to be those guys.
One was a bartender that was always drunk, he'd turn around and just scream at whoever his poor partner was, he was also the captain.
And in another match it started to get dark after the 2nd set of our outdoor match so my players and their players seemed to make it really hard in deciding what to do about playing out the 3rd set.
I think one guy on the other team must of had 7 beers in the time it took them to decide. (about an hour)
Finally they decided to go indoors to finish it, and this guy was still drinking on the changeovers (clearly he didnt care anymore but wanted to finish). On one point he was so out of it he appeared to be reading the writing on the strings of his racquet in the middle of the point seemingly facinated by them and my player hit a line drive screaming at him that almost hit him (he dropped the racquet).
There is plenty of time to drink after the match.
If you cant wait well then you probably have a real problem.
(Ive been to those mixers as well, I dont like those because Im pretty competitive and it's hard to be after Im full of beer / wine / and your typical party food that's not all that great for you.....)