Sometimes you have an opponent who travels as part of a pack, similar to wolves and hyenas. Wherever he goes, they go. They cling together, traveling from place to place. Every locale they enter, they take over and change the atmosphere. With loud and boisterous behavior, they overwhelm any other activities. If the environment was quiet and peaceful, they turn it into a loud, obnoxious party.
When you have to play against someone that belongs to this pack of verbal hooligans, you suddenly discover that you are not playing one person, but the entire group.
When your opponent is playing, everyone shouts and cheers his progress. When you shoot, the mob constantly distracts you. They are particularly insulting when you are trying to shoot. If successful, they shout obscenities and insults.
While gangs like this are generally low class, the lowest level of these groups goes beyond hurling verbal abuse. If you are beating their favorite, your life and limb can be threatened. If there is any amount of money on the game, they perform every type of mental intimidation their little minds can think up.
How you handle a group like this depends on your personality and experience. If you have dealt with such goons before, you can join in on their frivolity, and psych them into getting them to treat you as an equal. If you have a more retiring mindset, you may want to take the first opportunity to escape, with or without your equipment.
Generally, when a gang invades a business establishment, do as much as you can to fade into the background. Turn down invitations to compete by using the "don't know how to play" excuse.
Leave as soon as possible. When you have an opportunity, re-think your reasons for being in such places where a gang or two may use as their hang-out.