Luthienrising was saying she hasn't seen a mod, not a bike, as she runs the mod tracking thread. :lol:
Also, this is a bug. I remember some people discussing it before and running tests, but I don't think anyone made a mod to stop it.
https://answers.ea.com/t5/Bug-Reports/Sim-s-spawn-on-bikes-when-a-club-meeting-is-started/m-p/8632156/highlight/false#M119314
Someone in LMS's Discord posted this solution: "What you can do in the meantime is just invite everyone that are from the club to the lot (using the phone, not the rel panel), and after they all arrive then start the club gathering."
I want to make an entire "no bikes mod" for history players that completely eliminates bikes, but I wouldn't know where to block the spawning bug. I'll have to see if I can find it, but by the time I do EA might have a fix already. It's around that time we get an announcement and eventually a patch.