Scammers are all the while looking for means and methods to exploit bank and financial systems and, although this does appear to be a cute idea, it is always likely to fail with the requirement for an indemnity which is quite an important and serious financial document. I won't describe its function and operation in detail, as I'm not here to coach scammers (who may read this) but although an indemnity will bear an amount, the potential risk to the person signing it could be much greater as it covers the party being indemnified for all losses they may suffer as a result of paying you the stated amount, and could therefore include interest, costs and damages if the claim is unjustified, which we know it is.
As AJ states, a sudden rise in the number of these types of claims being made would very quickly be noticed and come under scrutiny. The scammer is being smart and ultimately stupid at the same time. Just because something is technically possible as a scam it doesn't make it worthwhile. I think this is one case, but it's worth highlighting it as anyone who does fall for it will lose money, not gain anything, and strictly what they're doing is illegal and it's being done in the victim's name.
CAR ADVERTS - If a car seller mentions escrow - he's scamming you Never ever for any reason pay anything until you have seen and inspected the vehicle