AbdulAlhazred
Legend
Given that surprise is just a standard action I wouldn't make Surprise as hard to achieve as
Manbearcat indicates, though. I think I would run it much as the OP's initial idea.
I don't think he's saying it necessarily has to be HARD to achieve, just that giving it out by fiat is disenfranchising the players to the extent that they may have invested in character traits for the very reason of NOT being surprised (WIS, Perception, Insight, possibly feats, items, fictional positioning, etc). Its the "no matter what choices you have made, you ARE surprised" which he is objecting to. Its a valid point. Still, the designer of the scenario is free to simply set a bar for not being surprised that is fairly high, yet it probably would be good to set it such that a character with say an 18 WIS or a 16 WIS and trained in Perception manages to avoid the surprise round.