Sometimes you book a DJ that you just can't seem to connect with. Maybe they are grumpy because they have been on tour for weeks and are just exhausted, or just got in a fight with their agent or spouse. I try to give them the benefit of the doubt as much as possible since you may not know their situation, but sometimes they are just assholes. For the most part, anyone you book is most likely going to be a chill person, but sometimes you can encounter that one ego maniac that just sets your blood on fire. Maybe this person just has a personality that clashes with yours, but gets along with most others just fine. Maybe they said a racist comment in the car ride from the airport. Sometimes they are totally normal until they start drinking, then become this uncontrollable monster. Whatever the case may be, just remember that this is temporary and there are ways to avoid interacting with them.
One way to avoid interaction with them outside of the venue, is to just pay them cash for dinner and ground transportation. Just tell them that you are busy and can't properly host them before the event. Sometimes you really are too busy, but for the most part, they can care less if you babysit them or not. They are adults and can check themselves into the hotel, go to the nearest restaurant, and hail a cab to the venue as long as they have the money and proper info. Many times it is actually a wonderful experience taking artists to eat and at least 95% of the time they are amazing people with great stories and senses of humor. This article is in case you are blind sided by that rare 5%.
If they are a mic hog, babbling nonsense to your crowd, unplug the mic right after you announce them. This can piss them off, but if you stay out of the DJ booth until the end, there is nothing they can really do. I only do this in extreme cases where the DJ does not know how to shut up or is insanely drunk. The mic can be your friend, or worst enemy.
I may even lock the DJ booth, so the DJ can't convince people who wander in to keep feeding them immense amounts of booze. You may even have a bouncer stationed. The DJ may think it is to protect them from the crowd, but it is really to keep the crowd safe from them. Keeping an alcoholic person sober, or at least coherent in a bar, takes a fine balance of being smart, but playing dumb. If they have a bad reputation of alcohol abuse, I may just give them 2 drink tickets, then say the rest are with my partner and I don't know where he is. My partner may not even be there that night. Sometimes it's not even the alcohol that is the issue. Sometimes they are just so full of themselves that being the center of attention turns them into fuck wads.
A lot of the time, the DJ is cool as hell, but it may be their girlfriend or entourage that is causing the disturbance. In this case, you need to proceed with extreme caution because what you say can easily be taken the wrong way. Sometimes emotions are high, and I have snapped before. It is not cool, to lose your cool. What I have learned to do now, is pull the DJ to the side and have a one on one talk with them about the situation as to not embarrass them in front of other people. They usually understand, and it is most likely not the first time they have dealt with the problem. If the shit hits the fan while the DJ is spinning, the best thing to do is try to keep the troublemakers in the DJ booth by themselves and pull everyone else out. Then just pray the shit doesn't get out of hand. Many times the entourage just wants to draw attention to themselves because they are not the superstar DJ at the center of attention, so they sometimes act out inappropriately. Maybe the girlfriend just has an ego because she is fucking someone famous. Whatever it may be, just lock them in there with the DJ and he will deal with it himself if they start to piss him off. I mean they are HIS friends right? So he may know how to deal with them better than you do, while you may just escalate thing and make matters worse.
Sometimes it is in a DJs rider/contract to have a ton of alcohol provided to them. This is a major red flag to me and I usually negotiate a more sensible drink rider. It tends to piss off a lot of artists and agencies because they assume you are being a bad host, but it is less about being cold to your guest and more about covering your ass. I have dealt with numerous issues dealing with an ego that is drunk. This is a dangerous combination and you have a lot of money, and your reputation on the line, so I try to catch the issue at the source. There is no reason why a DJ needs a full bottle of vodka, then be staggering drunk before they play an hour set. Since when does alcohol = good performance? Just do your job.
In some cases, the artist will expect you to provide them with hard drugs, and they assume you will pay for it. You pretty much have the right to tell them to fuck off if they are being rude about it. If they are chill, and maybe want to do something after the show, then I may connect them with a source, but I will never put my own ass on the line like that.
I have seen performers fight with people, argue with the sound guy, not allow the next DJ to start, stop the music entirely while they babble on the mic, train wreck, accidentally unplug gear, and harass women. It is not worth the risk, and don't let anyone guilt trip you into going against your premonitions. You are the customer and the boss here. You are the one taking the risk with everything on the line, don't allow yourself to be stepped on.