Quote from dnaj65000:
I had an error back in 2000 when I asked for a $11,000 wire to be sent to my bank account. They sent it twice and didn't notice it for almost 4 mos. However, their Reconcilation Dept finally caught on and I paid it back without a fuss.
I vote, keep it there and earn the interest. Of course, if you're willing to pack up all your stuff and move to a non-extradition country and willing to run from the IRS for the rest of your life (since I doubt you'll want to pay income tax on your winfall gain), then go for it.