Is there some sort of Escrow-type-thing that would work?
Or a lawyer that could act as middle man?

Holly crap! Did I just come up with a business opportunity here?!
Some untapped market where I turn up in a security van thingy and each party puts the
cash / item on a sort of ... revolving turntable setup!
And it spins round when both people and the "middle man" (that would be me) all agree !!
There could be coffee and donuts too. And free wifi !!

It was my idea. I came up with it first ...

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