A not so fond memory.

I sell my jewelry mainly at science fiction conventions. For a few conventions it worked out: my collection of books, fanzines, toys, hand made jewelry and so on was eclectic, and drew in a decent amount of customers.

It was a great environment with almost no rules: you could sell what you wanted. And this worked well, until...

And then one year I set up at at a small convention
. 100% of the dealers (50 at least, if not more) were selling the same sort of jewelry I was. The result was that nobody sold anything. Rules were quickly put in place after that, limiting the amount of jewelry sales.

As an aside, here is something I figured out one day at a convention: there were almost no sales that weekend, so I had plenty of time to do calculations.

Conventions with smaller numbers of attendees tended to produce more sales per attendee. Total sales were small. Conventions with larger amounts of attendees tended to produce fewer sales on average per attendee, but the sales in total were larger.

I presume this means that the smaller conventions have less dealers, and thus less competition, the reverse being true for larger conventions.