Of the literally tens of emails we've had over the years on this matter, they've all said pretty much the same thing. 'Scone' is posh. 'Scon' isn't.
Rubbish. 'Scon' sounds ludicrously posh. 'Scone' doesn't.
Don't believe me? Well lets try it. Go, put on your best thick Lancrastrian, Mancunian or Yorkshire accent. Or maybe a West Country one. Or Brummie. Done it? Good.
Now try saying 'scon', then 'scone'. Which sounds poshest? It's the former, every time.
Indeed you'll quickly find out that 'scon' sounds absolutely, mind-bendingly stupid said in these accents.