ok.so a little about me.
im 18, been bowling seriously since i was 6, and i've gone to my fair share of local and interstate tournaments.
majority of my leagues since i was 14 have been adult leagues. i currently bowl at mt gravatt on wednesday nights, and mt warren on friday nights... and i guess they are what you would consider "adult leagues".
I personally do not see a problem. it only gets the juniors ready for bigger and better things. alot of them look up to the adult bowlers, and i have seen many adult bowlers take juniors under their wing.
in all the adult tournaments i have bowled in, juniors have been more than welcomed into the tournament, in fact, they have been sought after.
to get bowling back into shape, we all need to encourage young bowlers into the sport, or at least into the competitive side to bowling.
i agree with what chris said. if your good enough, why do you care if juniors bowl?
and just to add to that, it shouldnt matter. i know lots of juniors that could kick the adults butts.
dont be scared of a little underage competition.