These are set and enforced by the ftp.crysp.org moderators.
CrySPers only. All members of this instance must be current or former members of the CrySP lab. As a rule of thumb, your name should be or have been on the CrySP People page. https://crysp.uwaterloo.ca/people/
Avoid posting NSFW content. Exceptions for content relevant to your research are fine, but must be hidden behind an appropriate content warning (CW).