Procedure at Security Checkpoint with SSSS
When a passenger receives SSSS on a boarding pass, what is the procedure in the US? Can the passenger still opt-out of body scanners? If so, if the passenger was going to opt-out anyway, is the pat-down any worse than it would have been if the passenger was going to opt-out anyway?
My understanding was that one can always opt-out, but I wanted to verify this information.