But is it reasonable to get the XP for the trap if you search every single room in a dungeon taking 20 ???
Where the sense ?
"OK, guys ! Another room, get out your lunch and start a fire for coffee.
Rogue ! Search ! Search !"
It's not fun to die because of a trap, but it happens every now and then. It's simply unrealistic to search every 5 ft square of a room taking 20. It's even unrealistic to search every single square of a rooms floor. I don't look 6 seconds before I make a step in a natural cavern, do you ?
I don't search places for traps if I never have the intention to go to that specific place. Imagine a room 30 ft x 30 ft. There is nothing in there just bare floor, wall, ceiling. Now you see a door to the left and a door to the right. Do you search the wall to the front because there could be a trigger for a trap ? I think you straight walk to one or the other door, search there, open it and walk through.
If you engage the whole party with low Search skills to search the room, it is most likely that you trigger the trap because you (the party) searched for it, not because you accidently triggered it.
As a DM I place traps where they are not expected. In the middle of a 5ft hallway or the like. (I hate playing NPC-wizards as dumb commoners.)
But the first character moving near the trap gets a spot-check (rolled by me, the DM). He has the chance to notice something unusual and then it's on the party to work it out. The rogue will most certainly search this specific area. If the search check says there is nothing special to see there he tells the other characters and moves on. Most of the time he will detect the trap. If not he gets a save or AC vs. the trap (nearly always doing the save and not getting harmed because of Evasion). In very few cases he will take the damage because of no save, no attack traps. And what ? The next fireball in a fight will equal this damage out with the fighter (who will most certainly take at least half damage).