Separate question. My parents are going through BOS. Inbound on EI into E, and departing from A on DL. It's 2 separate PNRs. If they aren't checking luggage, will it be an issue clearing customs (or do you have to do that incoming from DUB, or do all flights from DUB preclear customs?) and walking from the E to the A term in 1.5 hours? Thanks!