Maybe they simply could not sell you a bag. I am pretty sure Menzies at ARN are not a bag shop and maybe they do not even have a system to allow for on-the-spot sale.

Perhaps people are not authorised to do whatever they feel like just because a customer wants something. If we go by "do whatever to please people", where do we stop? There are things like conventions and contracts in place for a reason.

There are also people buying travel insurance for a reason...