This is literally why I said it would sound suspicious. Most people wouldn't be able to tell. Which is why I said you'd need to provide some kind of sufficient proof of your identity (or some adequate alternative) to address their fears.
If not, another one I was thinking was asking them to meet at their local police department and looping in an officer into the story or something. Different things work for different folks so they'd have to get creative to find the right solution.
Oh wait, I believe these are called notary offices in meatspace!
(tangent: at some point I thought that maybe notaries could sign one's PGP key instead of relying on rare/non-existent signing parties)