Moderation and Randomization

There is a curious dichotomy  in most gaming philosophies. It is the roleplay vs roleplay, that age-old argument.

Consider this:

The party enters a seemingly empty room, which the DM describes thus:
"It appears to have served as sleeping quarters. There is what appears to be the remains of a rough cot, along with a shattered chest, and curiously, a moose head hanging askew on the wall to your right. What do you do?"

Party A
(Thief) "I give the moose head a good once-over."
(DM rolls a successful check, but knows there is nothing there) "You don't notice anything out of the ordinary."
(Thief) "No hidden compartments or triggers or anything?"
(DM) "Nope. Just a lot of dust and a definite funk in the air."
(Thief) "Alright, how's about that cot?"

Party B
(Thief) "I carefully approach the moose head and, without touching it, look at it carefully for any signs of tripwires or disturbance on the wall where it is mounted."
(DM, going strictly with player description to inform what the character perceives) "You don't notice anything unusual."
(Thief) "Ok. How many spikes are on the antlers? I carefully move the left ear clockwise. The right counter clockwise. Both of them at the same time in opposing directions. If there is a tongue, I pull it out and swirl it around. I try to push in the eyes." Etc etc etc for the next 15 minutes.
(DM knows there is nothing there) "You don't notice anything out of the ordinary."
(Thief) "Let's move on to that cot."

Why are these two methods always portrayed as being mutually exclusive? It is odd to me that a lot of gamers are fine with randomly determining some things, but call random determination of others utter bullshit. A lot of old schoolers despise the idea of any kind of Spot/Notice/Search checks. I've read of some that won't allow a thief player to roll to disarm a trap unless the player describes how he's doing it.

By the same token, I don't like the notion of the party arriving at a tavern and having the bard's player say "I toss 20 gp at the barman for a round for the house. That should give me a +2 on my Learn Rumors roll. Aha! 20! What rumors do I hear?" I prefer a game where player description and roleplay are part of the process, not ignored and not all of the process. A game where a brief description of looking in the moose's mouth and twisting its ears might grant a bonus.

Nothing should be automatic, based solely on player description. I have been looking directly at something I've been searching for and still not seen it. I've dumped everything in my backpack on the ground and still not found the Clif Bar lurking around in a nook in the thing. A thorough description by the player shouldn't grant automatic success. I like some randomness. It makes me feel more like I'm exploring and discovering the dungeon right along with the players.

The bottom line is, RPGs are, at their core, playing make-believe. The rules for rolls and randomizations keep us from devolving into the arguments we had as children. "I shot you!" "uh-UH, I shot you first! I already called it!"