I made the mistake twice, then learned my lesson.
On a separate note from how dougz decides to implement tools, from a rules perspective I've never understood how rules like this are interpreted this way in gaming. To me, intuitively, when I see "You may return three cards from your hand", it means that I can return 3 cards, all at once, in one shebang. Like in Monty Python:
And the Lord spake, saying, "First shalt thou take out the Holy Pin. Then, shalt thou count to three. No more. No less. Three shalt be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out
In my humblest opinion, I think this counterintuitive nature of the card is more to blame for confusion than for how dougz decided to implement it. If the card was something like, "L: You may return a card from your hand. If you do, score two cards of value one less than the card returned. L: You may return a [3] from your hand. If you do, draw 3 [1]'s." I think people would intuitively be looking out to see which effect they were returning to.
In fact, I'm not sure I've ever seen anyone return a 3 and two other cards and then tell me they did so by mistake. They tend to recognize that they have the ability to comply completely with the first may-offer.
This isn't unique to innovation at all, ftr. An opposing Vault from Dominion lets you discard one card, but then draw nothing, if you only have one card in hand. And Mind Rot from MtG is an instruction that is half obeyed when you use it on an opponent. I think it dances around stuff like Tools by having costs work differently from effects though.
