The most ambitious / outrageous scam that I have ever heard of, has to be one which has been perpetrated on occasion, for many centuries past, by Gypsies. (Would emphasise that I harbour no hostility toward Gypsies / Romanies: am just, for interest’s sake, telling about stuff which people sometimes do.)
This manoeuvre is called, in the Romany language, “hokkani boro” – the great trick. It involves convincing the “mark” that their financial wealth is, “in whatever way”, possessed / contaminated by evil; and that great misfortune will come to them, if they don’t let the scammer deploy Gypsy powers / wisdom, to cleanse their money from the evil that besets it. The “mark” is told to convert all their money into cash, make it up into a parcel, and hand same over to the scammer, for the necessary rites to be performed. The scammer returns an identical-looking parcel – containing, of course, torn-up newspaper or the equivalent. Strict instructions have been given, that the victim must not open or in any way tamper with the parcel until such-and-such a time-interval has gone by, as that will undo the spell...
Part of me, considers this a diabolical thing to do. With another part, I feel a little bit of sneaking admiration for the sheer ingenuity and audacity involved in bringing off such a feat; plus – other than in the case of confused old folk, or others who are clinically “cognitively compromised” as Pippen puts it – a bit of the sentiment that Darwin is in the picture here: anyone dim enough to fall for such a preposterous yarn, maybe deserves to lose their life savings.