Perhaps I'm just being hypocritical in this though.

Confirm. ;) (Nope, I didn't misinterpret it as EU.)

Even if people recognized the ambiguity, it's not obvious that one should go for an intermediate answer rather than putting all one's eggs in one basket by guessing which was meant. If I were taking the survey and saw that ambiguity, I'd probably be confused for a bit, then realize I was taking longer than I'd semi-committed to taking, answer make a snap judgement, and move on.