SCSN would do that mistake on ISO too. But he would be able to buy something else than DC.
All true. When a user makes a mistake, a UI generally shouldn't pour salt in the wound, and having him accidentally buy DC is just that: a further penalty on top of playing a BoM that does nothing. So SCSN's mistake uncovered what I'd consider an interface design problem.
Right. The same thing happens with, eg, Swindler. I played a game a couple weeks ago where my opponent
bought a Curse two turns in a row, because he thought he was swindling my Shelters.
The solution is easy: have "name a card" look even a little bit different from "buy/gain a card" (you can distinguish between buy/gain if you want, which might relieve some HoP accidents, but I don't think it's a high priority). For example, use the blue "+" sign for buying, and a green "o" if you're naming for some purpose other than gaining. You could even put it on the left side of the card, so that when SCSN eagerly clicks in the spot he expects the green "o" to show up in, there's not suddenly a blue "+" there.