sweet feet: I know I'm being dense...and thank you for helping me understand this...but here's my next question.

By "SC" I take it you mean the SCYSA. Now, the SCYSA, and for that matter its parent the USYSA, by USSF ruling, can't prevent a player or team from being registered with both the SCYSA and USCS.

How can the SCYSA prevent a player from being dual registered with any other USSF-affiliated organization? Is that written into the USYSA rules and regulations that its affiliates have the ability to prevent that (since I know that it's explicitly allowed by the parent USSF organization)?

I'm not trying to be tricky here -- I think you know something that is true and I'm just having trouble grasping it. Thanks for your time on this.