1) I think this is bad tactics. In fact, teams quite often say the right answer after clue 1 (I'm sure it's happened around 5 times this series already). It's then down to whether the second clue confirms their suspicions sufficiently. Personally, if you had even a 40% chance of getting it right by gambling on the first clue, I think it would be a beneficial tactic.
2) I would agree with this. The Chessmen certainly threw away 5-10 points on both of their appearances by asking for too many clues. However, it is hard on the teams because they only get 3 questions per round at the start of the show, and they don't want to look silly by buzzing in and getting it wrong.
David
(OC Question Editor)