Is it possible to stay anonymous when joining a private tracker community?

I was just reading through the interview process for RED, and they specifically forbid the use of VPN during the interview. I don't understand this requirement, and it seems like it would just leak your IP address to the IRC host, which could potentially be used against you in a honeypot scenario. Once they have your IP, they could link that with the credentials used with the tracker while you are torrenting, regardless of if you used VPN while torrenting.