She won't be booted out of the airport.

As for being most comfortable in a tough situation, I'd probably leave the arrival concourse and head to the Seabourne gate area.

She could also ask a flight attendant or a gate attendant on arrival if the airline has a " club" lounge at SJU, and what the hours would be. Sometimes, 20 bucks or so is all you need to get in, and it would certainly be more comfortable than in terminal seating.