Gatecrashers can ruin parties. So, to avoid spoiling your party, here is an effective way of dealing with party crashers.
1. Study their behavior.
After finding out that those people are not invited, watch and observe their actions. Carefully study how they behaved without being obvious. What do you think is their purpose of going to your party uninvited? Did they come because of the food and drink? Are they posing aggressive or disruptive behavior? Are they mingling with and causing trouble to your guests? Observe them and ask a few of your friends to do so.
2. Figure out if they are troublesome or not.
After watching them for a while, you will be able to know if can or will cause trouble and ruin your party. Talk to your friends you have asked to observe the gatecrashers about what they think of them.
3. Decide if you will let them stay or escort them out.
Many times, people walk into a party uninvited just to have fun or some thrill, or for free food and drinks. At some point, you have to approach them and politely ask them who invited them to your party. If they say, they were invited by one of your guests who is present, approach and ask that particular guest they are referring to. If they were actually invited by one of your invited guests, then you might want to consider letting them stay. If they are really gatecrashers and do not mean any harm, go with your instincts and consider the observations you did earlier. If you feel they just want to have pure fun and would not bother any of your guests, they you can consider having them. But, if you feel and see that they can become a threat to you and your guests, politely ask them to leave. Tell them with all kindness and firmness that your party is private. Do this with some of your friends. Approach their group without being too intimidating or threatening, otherwise you might trigger a commotion. If things get to worst, call the police and let them know what you did. That will serve as a warning for them and hopefully they will leave without making things worse.
5. Talk to your DJ for hire.
Your DJ can do so much in maintaining the happy and relaxed mood in your party despite the presence of gatecrasher who try to make some trouble. When you go for DJ bookings, talk to the DJ of your choice and make a plan on how to handle such a situation. You can talk to him that once he observes that a little commotion is going on, he could get the attention of your guests away from the trouble going on with the gatecrashers. He can ask your guests to dance, play a game, or anything that would make the overall mood of your party normal and not intense.