Depends on which team you are considering. Some are just groups that play events together casually (or more than casually), while others have very strict guidelines.
The ones generally "available" to inquire about further here in the forum is TFB (Team Fug Bug), FFF (I always thought this was Fightin' Frank Forever, but they may have changed), and I believe the Pirates, and Wicked crews.
Gang, care to share more?