Ben was waiting at the rental counter in Oakland. He had to wait for me to pick him up as he lost his wallet at the airport (the one before he got on the flight).
Anyway, he saw people at the rental car desk running into problems as they had checked AM instead of PM on the website.
This is why 24 hour time could make sense in some way. 12 hour time can be good when you have the context of the time of day, but 24 hour time isn’t ambiguous.
Even in places where 24 time isn’t used, you could put that time in a subtle place on the interface and it could be enough to stop this issue.
Or, people could not be dumb. That won’t happen.