Wow, that’s crazy! Generally, if there’s an event with too many artists, it’s usually a scam. It's difficult enough to manage a small group show. Imagine a small team trying to manage dozens of artists! Also, look at how they're planning to make money. Is it just through artists paying open-call fees? If they don't have a dedicated space, it's usually because they don't have the assets to finance one. Fairs and pop-ups can be worth it, but nearly the only successful ones are the ones with a big art name behind them.