Gate crashers

I had gate crashers at the Wedding Show last Sunday. Gate crashers! How can that be at a public showing? Apparently they came before the show was opened and distributed their books.
Kind of sneaky, don't you think? In other words, their vendors got in for free while my vendors had to pay for the privilege of being in the show.
I intend to send them a bill. There has to be a high price for gate crashing, right?