Originally Posted by
WineCountryUA
Having done some googling this does appear to be the critical point. I'm well outside by expertise but I would have though UA would not issue a faulty ticket.
If BPs were issued at check-in, what would cause AC then to deny boarding? It would seem the issuing of BPs would be the point to catch this issue.
Agreed -- but IME, UA won't issue boarding passes for the next day's travel if there's an overnight transfer. (They do for a red-eye flight, but not if you're arriving one evening and departing the next morning). So I suspect OP would have to check in with AC at IAH to get boarding passes, at which point I'd expect they'd be refused.
It's also entirely possible that AC wouldn't notice and would let the flight proceed. And, as
mahasamatman pointed out, the passenger wouldn't be in any trouble anyway; it's AC and/or UA who would. (UA for selling the ticket and AC for operating it).
Unfortunately, given the routing involved, I suspect we'll never know, because I really doubt OP is going to book it.
