I have noticed that a lot of the /script commands are case sensitive meaning
/script AcceptBattlefield(1,1,1)
is not the same as
/script AcceptBattleField(1,1,1)
****note the "f" in field*****

But that's not a script command

I use
/script AcceptBattlefieldPort(1,1)
to join BGs all at the same time and try to get in the same group that way.