Thats a unique angle there to get to know somebody...I remember something similar..had a stranger knock on my door once, He had taken an aerial photo of my farm and wanted to sell it to me for $100...It looked nice, taken at the perfect time of lighting etc...framed and all...I never asked him to do it though, so it took me by surprise..
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Then I thought, what kind of a deal is this?...Who else would buy a pic of my farm? And who else would want to see it or even care?
But I was in a generous mood that day I guess, appreciated his moxey and aeronautical photography skill, so I offered him a dollar...!!
Mud
(true story!..Wife can verify, she was mad/ashamed of my negotiation skills for some reason? Insulting a stranger? I never asked the guy to do it in the first place! How did all of a sudden I become the bad guy? Still, she was mad at me for being so rude. So in the end, that Cessna flying Ansel Adams bastard freaked me, but at least It didnt cost me any money....so Yeah, if you was to show up on my front porch and pitch this deal, I'd say "sketch away!" I'd probably even give you a handful of Wheat pennies for your trouble!)