I don't think your analogy works the way you want it to work.
If players are burned by a DM who says "you searched the room but you didn't search the box because you said you searched the room not the box" or "you searched the table but not the drawers for traps" or "you searched the chest for traps but not the lock and this trap was on the lock", they will generally (assuming they continue to play with that DM) begin to ask "I search the room. Are there any boxes in the room? I search the boxes. Are there any tables in the room? I search the table. Are there any drawers in the table? I search the outside of the drawer for traps. Is there a lock on the drawer? I search the lock for traps. I open the drawer and search the inside for traps. Then I search the drawers," instead of simply saying "I search the room." That's not an argument for making search a passive skill but it is a very good argument for making search apply generally to things like "rooms" or "chests" rather than specifically to things like "box 1, the table top, the chest's lid, the chest's body, the lock on the chest, the floor under the chest, and the wall behind the chest."
Search is widely recognized as a skill that only works when active. The question is
how active it is. As you recognize, that it is active doesn't have to slow the game down as much as the bad example indicates.
Sense Motive, however, is quite different from search. For one thing, it is the opposition skill for bluff. And that "opposed check" use is the one in which there is question about its active/passive status. A better analogy would be to the spot skill which is the opposition skill for Hide. A DM who made a policy of allowing all hide checks to succeed unless the PCs asked for a spot check (while, naturally, all NPCs "ask" for spot checks against the PCs' hide checks) could expect to have every player start each round of combat and each entry into a new area with a dialogue like this:
Player: "I'd like to make a spot check to notice any hiding rogues or assassins--my spot check is a 25."
DM: [pretends to roll a hide check behind his hand] "if there are any invisible assassins or hiding ninjas in the common room of the inn, you don't see them."
Player: "OK, I'd like to make a spot check to notice if anyone in the bar is really a ninja assassin in disguise. This time the spot check is a 19."
DM: [pretends to look through his notes] "If there are any disguised ninja assassins in the room, they are convincingly disguised as dock workers and fishermen."
Player: "OK, I walk through the tavern to the outhouse. I'd like to make a spot check to notice any hiding rogues..."
Clearly, that's a pretty ridiculous level of attention paid to spot checks though it's necessary if spot is to have any use when treated as an active skill.
Sense motive is more like Spot than it is like Search. Like NPCs always know to ask for a Spot check vs. the PCs' Hide, the NPCs always know to ask for a Sense Motive vs. the PCs' bluffs. On the other hand, it's quite reasonable to suspect that an NPC would not think to search square 37 in a 50 square long corridor. Also, like Spot (and unlike search), Sense Motive, is something that is primarily useful when you don't necessarily have reason to suspect that something is up. The character walking out of the tavern has little reason to suspect that there may be hiding or disguised ninja assassins in this particular tavern at this particular time even if he has good reason to suspect that sneaky ninja assassins are after him. Similarly, the character being hired for a dangerous archaeological expedition has little reason to suspect that this particular employer is setting him up as a patsy on this particular mission even if he has good reason to suspect that one of his employers might try to set him up as a patsy at some time in the future. Like Spot, Sense Motive needs to be used constantly if it's to be helpful. And Search, unlike Spot or Sense Motive, is the kind of thing characters only do in exceptional circumstances (exploring a dungeon or looting a room).
Since Sense Motive is more akin to Spot than to Search, it is reasonable to believe that making Sense Motive active only is going to result in "is he lying; my sense motive is a 27" as soon as an NPC so much as says "My name is Bob and I have a proposition for you" in any game that involves intrigue.
StalkingBlue said:
Neither is true for my games.
And forgive me for pointing this out, but players burnt by a GM who's not trustworthy are a problem all by themselves - they need remedies tailored to their maimed condition. The ways burnt players tend to think and act and ways to heal them are hardly relevant for a discussion on rules.
To illustrate: I think we can prob all agree on Search being an active Skill, yes? No Search rolling unless the player states their PC is searching? Players burnt by a bad GM may be found cutting everything and everybody open, and spending an entire gaming night searching and re-searching absolutely every square inch of every floor, wall and ceiling they encounter, whether for treasure or for traps. Using such players' behaviour as an argument for making Search a potentially 'passive' skill like, say, Spot isn't going to work all that well, is it?