That seems reasonable, would be a good solution. Being killed by a trap that cannot be detected in any way seems very unfair (especially if they decide to implement iron man and someone doesn't play the game in lower difficulties first).
If someone is hardcore enough that they choose to play on the no-save difficulty as their very first time, then I don't really think they have cause to complain.
I think they would. Even in iron man, the game should be very hard, but beatable with enough skill and care - and not just because the player already knows everything.
(i plan to play the first map on hard until i master the system, then start a full game in iron man - if necessary i'll split the party for grave digging, but i would prefer Gnosters solution)
