You have to remember, Mac is not making anymore plugs and have a good reputation of catching, so they fetch a few more dollars now that he is no longer building.
I think it obviously would bother the original builder if a plug or plugs were given to someone and they then turn a profit from it/them. But once it leaves your hands, you have no control over what happens to it.
what if a plug you donated to a fundraising raffle sold later on for big bucks by the winner ??? nothing much you can do about it, he won it fair and square and has every right to sell it or fish it or collect it.
If plugs are sold, there usually is a reason. sometimes ya need the money more than you need the plug anymore. I make a point to not sell any that were given to me, but if I have to sell some swap plugs or plugs I bought, I will if I need the money more than I need the plug and I'd hope the builder would understand just like I understand when others do it.
I've given away way too many plugs in the past and now a days I just lose them to trades, fish and operator error
.
Plugs are like your little children,
scared to let them go.