Coinjoins are not "very select parties" where 10 people are "specifically chosen" to attend. It's the exact opposite: Coinjoins are open parties where the dancers specifically choose which party to attend.
If they are allowed to enter. They are public parties you can freely enter if you fulfill the requirements of their co-host. The co host checks your clothes, your date, how much you weigh, how your hair smells, and the color of your eyes. If everything is OK, you can come in. Our partners will keep a close eye on you though. If we notice something iffy about you or something we don't like, you aren't coming in to our free public party. The co-host is a symbol for Wasabi's blockchain analysis partner.