r m a h

with a same day boarding pass, has anyone had any luck accessing a terminal in BOS that they are NOT flying out of? i.e. if you're flying southwest, but you want to access terminal B so you can go to united lounge? is it strictly prohibited or possibly possible? i've asked a similar question, and the only advice was to buy a refundable ticket. but i would like to avoid this option....

thanks,
rh