Originally Posted by
seoulmanjr
OK - Devil's advocate:
Where do rights and ownership come into it? Don't the airlines FF programs T&Cs maintain that they own all miles and accounts and the airline has the right to do as they please when they please? As much as we on FT might like to think of it that way, these aren't bank accounts. If an extra $50k showed up in my bank account in error and I spent it, I'd be legally liable to repay the money. If an extra 50k in miles showed up in my FF account and I blew it on a RT to Europe and the airline didn't come across the mistake until after I'd completed travel, tough luck for them. Most people out there have no idea what their FF mileage balances even are.
I've personally had instances where 15k miles have suddenly appeared in my account as compensation for a bad mx delay weeks previous. I didn't request compensation and they didn't tell me they were giving me any -- the miles just showed up. Sometimes it happens (twice to me, at least).
Cancel that devil's advocate bit up above -- I convinced myself.

peace,
~Ben~
So, at the check out line the clerk mistakenly places another customer's items in your bag that you haven't paid for. You get out to your car and find them. It's now okay to keep the items because it was a mistake and it wasn't currency?
Those who steal or keep items that don't belong rightfully to them, causes a negative impact to everyone else who participates with that company. Lack of responsibility to do the right thing hurts everyone.