I've had quite a bit of experience w/this with regards to my son. Unfortunately there is no concrete answer. Legion ball today is nothing like it used to be. American Legion ball has sat back and watched the showcase/travel team business turn them into an irrelevant operation. I've read the national rules and know them quite well. My experience is the rules are followed by no one. Every state , district , county , team does whatever they want. In NY players are playing on travel teams and legion teams all the time. It's been going on for years and it isn't going to stop until legion baseball is gone. That day is coming. I've talked with the national director about different rules , interpretations , applications etc. Also spoke with state commisioner , county director etc. and ended up at the same place. None of them care , none of them will enforce a rule or anything else. It's unfortunate because there was a day legion baseball mattered. Those days are gone and they have no one to blame but themselves. Is someone telling your son he can't play because of dual participation ? I've actually see players who are college kids playing in a summer college league and Legion at the same time. In NY it's commonplace for teams to be recruiting players from all over. Used to be a kid had play for the team closest to his school district. Up here it's become a joke,so have the results. If i were you i wouldn't even consider asking for anyones ruling on anything. I'd just go play ... or tell your son to just go play , whatever the case may be.