There are some who have been wedding crashers and have the inside scoop about how to see the tell-tale signs. Here are ten insider tips about how you can determine if one is present or not:

1: Grandmas has a dance partner

Theory of the Crasher: if he dances with the older woman, whose memory is terrible, she’ll assume he’s a friend of the family, and will earn him credibility instantly. This guy shouldn’t be trusted.

2: He never has the same story

A Crasher Trick: he’ll tell the bride’s side that he’s with the groom and he’ll tell the groom that he’s with the bride. Not only is this trick sneaky, it is also effective. If the bride and groom confront him together, however, he’s sunk.

3: His personality is too out-going

Crashers always want to be Vince Vaughn so they attempt the bro-hug with the groom, a dance or two with the bride, cutting the cake, and a speech that will raise everyone to their feet. In reality, wedding guests just don’t act like that. If someone all of a sudden does, you likely have a crasher.

4: You have a late comer or a rude receiving line pusher

A crasher will either avoid the receiving line completely, or enter the reception after the speeches have already been made because everyone is already on their feet milling around. This is when your guard should be up.

5: You’re getting faked out

There will be some ready-made story about how you and the crasher know someone together, like “Jack from high school,” and how you all had crazy times together. Then he’ll grab your shoulder to add to the charm.

6: They never sitting

He’s never sitting down and, if there’s assigned seating, he’s at the bar or in the bathroom. This person is always on the move.

7: They steer clear of the wedding planner

Your wedding planner knows how to spot a crasher, so they stay far away from them.

8: He’s a distant relative

He’ll come up with a strange story like he’s a fifth cousin or something like that.

9: Absent from the ceremony

The crasher is at the reception, but not at the ceremony. So, ask him pointed questions about things that did not happen at the ceremony to throw him off. This will catch him in the act.

10: He dances a little too well

Crashers spend all of their weekends at weddings, so they pick up a few dance moves. They’re going to be a bit too confident on the dance floor.

Now that you have found the crasher, what do you do? More often than not, aside from being a hassle, it should be taken as a compliment. You’ve thrown a great party, you have a funny story, and you’ve created some great memories.