No, and that analogy doesn't make sense. Presumably if you bought a gift card for someone you would... give it to them directly. This is someone who says "You need presents for your friends. I will sell you gift cards to their favorite stores! But you can't take the cards and give them to the friends. Instead, I'll hold onto them until your friends come and establish a business relationship with me."
No, you should be asking "is it unethical to ask for donations on behalf of an unaware 3rd party and not send the money unless the 3rd party proactively contacts you and requests it"
But you get the gift card when you buy it. You can then give it to another person. The thing of value is in your possession the entire time.
Funny you say that. This makes me think of gift cards in the sense that I suspect they will have thousands of tiny balances that are never redeemed. Usually you lose any balance after X years.
They do have thousands of tiny balances that are never redeemed and that's exactly why places are now issuing gift cards for rebates and such. That balance you don't use usually goes right back to them.