Personally, I'm inclined to agree that companies handling money need to be extra careful not to give the appearance of dishonesty. That said, I can see why you

Personally, I'm inclined to agree that companies handling money need to be extra careful not to give the appearance of dishonesty. That said, I can see why you might think it odd to object. All these people have done to respond to your offer is hit Reply, typed a couple words, and hit Send. It's not like you have some of their money. On the other hand, why not make good on your offer? Tell them you haven't actually built it yet, but if and when you do, the offer is still open... and then keep your word.