YHWH wrote:This issue comes up with a few of the Thief skills. I think the best way to handle these situations is to give the Thief both rolls at once: the percentile roll AND the 1 in 6 that everyone else is entitled to.
(I like this because it puts Thieves a cut above in this area, like they're clearly meant to be, while being more of a rules interpretation than a blatant house rule.)
On the other hand, there could be some other difference between the two rolls. Like the time it takes or maybe active vs passive. It specifies that the search everyone gets takes 1 turn, which is 10 minutes in game, which is not fast. (It's 1/6 the life of a torch and half of a wandering monster check.) I don't think it specifies how much time the thief skill is supposed to take. If it's faster that would be an advantage.
Some rpg-archeology-thread I found about B/X said that this was the correct interpretation in the sense of original intent, and also something about that the thief skills were supposed to be very quick compared to the ordinary trap-search that everyone can do. Thief skills were supposed to be almost magical in nature ("Hide in shadows" would mean that the thief could litterally hide in a shadow in plain sight, "Move silently" would mean that the thief did make no sound at all - being impossible to hear even for dragons etc).
OT: Thiefs "Climb Steep Surfaces"-skill is gravely under-used if you choose to play like this. It does not specify speed of climbing, but probably exploration speed at least? Even a lvl 1 thief would have a decent chance of climbing laterally on the walls of the labytinth instead of walking, avoiding all pit traps and stuff on the floor. If the walls are high, the thief could probably avoid a lot of encounters as well.