In response to this ad dealing with out of date bearer bonds (which have been illegal to issue since 1982 in the US), we have a clever reply:
I have a seller looking to sell a bridge in Brooklyn. Seeking serious buyers only. NYC procedures only. Bridge is not located in a bank because the seller would shut down the entire global financial system if the world new just how much he was worth. Seller wants 300T+50T Euros (paid in cash) for the bridge. Seller will have the bridge physically delivered via bank courier to buyer upon payment. If interested please email me at firstname.lastname@example.org
That's how most of these offers sound. A little common sense will tell you that these bond deals are COMPLETE NONSENSE. When in doubt, just use common sense.
350 Trillion Euros would be roughly 419 Trillion dollars. An unlikely amount to be in cash, much less as pocket change for someone posting blind ads over the internet.