Originally Posted by
teemuflyer
Can't even access it if you're arriving from an Int'l flight since the AC is past security which you'd need to pass through after clearing Immigration & Border Control, and without a valid BP, that won't be possible.
But as noted above, OW rules require a "departing" OW flight for access based on tier status.
LGA doesn't have INTL service AFAIK (YUL and YYZ have preclearence)...