I don't know you Patton, but I have read a number of posts from you on this forum while lurking on here for some time. In MHO I think the deal was fair and square. You didn't force the kids to give up the coin, you simply asked to buy the coin from him.
He offered you a price and you took him up on the offer.
I think most kids now a days are more 'street smart' than you think. I think if he had known the coin was more valuable than a mere $1.00 he would have asked for more.
The deal was struck, you gave him your card with all the info he needs if he gets into trouble due to his actions. I think your in the clear, and it was a great find. I would have been afraid to offer him more, for fear he would buy cigerettes, or something worse.
It was a fair trade in my book.
And I'm sure your card got lost in the wash, or found its way into the nearest garbage can.
Thanks, I appreciate that. I'm old school and I forget sometimes how kids are more "street smart" than I was at that age. With the internet, computer, and so many means of getting info, kids today knows what's happening all around them. And I agree with you on the card. I'm sure its a goner.