Player: I search the door for traps.
DM: [rolls] If there are any traps you don't find them.
Player: I take 20 searching the door for traps. After all, it says "Abandon all hope ye who enter here." That's got to mean something.
DM: You set off the trap. Make a fort save.
Player: But I didn't open the door, I was just looking...
DM: Roll.
Player: [rolls] 30. But I was just looking...
DM: You didn't say you were looking for magical traps. Searching for holes would have been OK but this is a MAGICAL trap.
Player: whatever.
DM: The DC was 29 so you only take 50 points of damage from the horid wilting.....
Later in the game
Player: So we search the room for the lich's phylactery.
DM: [rolls] You don't find it.
Player: We take 20.
DM: You still don't find it.
Player: Fine, we move on to the next room.
Much later
Player: The cleric puts his phylactery of undead turning in the bag of holding and casts locate object on a phylactery.
DM: The spell leads you back to the previous room and to the underside of the table.
Player: But we already searched this room.
DM: Yeah, you searched the ROOM but nobody said you searched the TABLE.
Player: Isn't the table a part of the room?
DM: No. That doesn't work for tables.
Player: whatever.
DM: Allright already. You also find a bunch of gold in a box in the northwest corner.
Player: But we searched the room.
DM: You searched the ROOM for the Phylactery; you didn't search the box for TREASURE.
Player: whatever.
After the game
Player 1: I'm not sure how to put this politely to X, how about we suggest it's time for a new campaign or you say you'd like to run a game for a while.
Player 2: Yeah, I guess I could do that.
One of the high numbers on the list of annoying things DMs do: Making you specify what part of everything you're searching for. It's not as if competent characters who are searching an area wouldn't search for everything interesting. It's not as if rogues who know about magical traps and apparently have some method of observing that they're there (perhaps the telltale shimmer of magical energy that's more noticable when mutliple abjurations are close together is something they can spot, maybe they spot faint traces of the runes that were part of the casting, or maybe rogues just develop a 6th sense about such things (they develop a pretty darn good 6th sense about combat (can't be flanked), so that's not much of a stretch)). In any event, the point of searching for a trap is so that you don't set it off. And if rogues are competent to search for normal traps without risking setting them off, they'd be competent enough to do the same for magical ones.
In any event, low level use of magical traps either assumes that all rogues have some kind of feat, a +search magic item, maxed ranks, and a decent int, that rogues will be able to take 20 or both/either. A first level spell trap has a search DC of 26. A third level spell trap has a DC of 28. If you don't want rogues to either be entirely tricked out (lens of detection, max ranks, skill focus, etc) or not bother at all about searching for such traps, you'd best leave the take 20 rules (or at least the retry rules--and that amounts to pretty much the same thing) for search alone.
Rogues already have good reasons to get good search skills as I described above. However, the take 20 rules gives them some bonus for having decent (but not maxed) search skills. When the rogue has time, he will still be able to find the traps in obvious places (like the front door of the dragon's lair or the chest in the BBEG's secret stash--assuming the BBEG is dead already, if he isn't, you probably can't afford the time) though traps in less obvious places are likely to get that rogue.
Nifelhein said:
If a rogue ever searches for holes that is okay but what about a magical trap? Is it possible to locate it by looking at the area? i don't think this would stand true for all the traps. take 20 may have a bad result or not, depending on the actual trap and the mechanism of triggering it.