Traps without locks would be extremely unwise for actual use.

Think about how you could trap a chest or door such that it would do bad things when opened. Now think how one would safely navigate the door at will.
On the other hand, a locked door can be trapped somewhat more safely: the trap can be connected in such a way that a key can disable the trap without exactly disarming it (mechanical stop on a critical component of the trap)

So... why trap an otherwise open door when there's no effective way to use that door when needed?

Cuz people are dikes?

In Morrowind this happens a lot actually, both doors and chests that are only trapped not locked, I liked it, especially since all of the traps in MW are magic so there's no mechanical anything to figure out - which doesn't make any sense that you'd have to disarm it with a probe...come to think of it...

They may be unwise for sure but that doesn't mean the NPCs in TES have to be anything but...

Yes, traps in Morrowind were all magical of some sort - or at least, they appeared to be.

Which is probably why I like the idea of containers and doors that are simply trapped, not locked. Sorcerers are perfectly capable of disarming a trap without using a key or a probe - that's what mages in Morrowind could do with Telekinesis. So it's logical that they trap containers/doors without setting up a way to disarm it again, because they have their own way of dealing with that.

As for the reason why they should not also lock the container/door if they already go through the trouble of setting up a trap... maybe they lost the keys? Other than that, there are doors that don't have keyholes (secret passageways or simply strange doors).
I don't think it should happen very often that a container/door is only trapped, but having the option would certainly be nice, and some situations might benefit from it. I guess anyone can see that a door/container is locked in some way, but a trap, especially a magical one, might not be detected so easily - nasty surprises, here we come!
(Based on the assumption that you can only see that a door is trapped by making a successful skill check.)

Traps and locks.

I thought Fearabbit's suggested system was quite good. An expanded version of Morrowin's. I would like to see, though, being able to smash or blast open chests. If they're trapped, the contents inside could be destroyed or damaged, or the smasher or blaster would be damaged. This would give the thief the advantage of disarming traps over the mage or warrior.

Also, seeing traps that aren't magical. Things like rocks falling on you if you open a trapped door, an arrow or something shooting you if you break open a trapped chest.
Still have magical ones too though.

Haha!

I loved traps in Morrowind! I used to make unlocked, trapped items (doors, rugs, chests) with the CS and then put more of them into the game. It kind of defeated the purpose, though, because I knew where the traps were. :facepalm:

I could live with either MW's or OB's lockpicking systems, but something in the middle would be better. Having the mini-game's difficulty DRASTICALLY affected by the difference in your character's security skill versus the difficulty of the lock would be ideal, in my opinion.

Your starting character, with no Security skill, would be semi-challenged by an easy lock, so the mini-game would be challenging, but quite "beatable" by the average player. As characters skill rise, easy locks would become "cakewalks", where you'd effectively stab the lockpick at it and open it. Encountering a "Difficult" lock, on the other hand, everything would seem to be "hair triggered" and touchy, to the point where it would be next to impossible for the player. With a bit more skill, the timing and sensitivity would ease up to where you could effectively "play" the mini-game.

An effective limit of about 10 points above and below the character's skill would be "normal", with anything above quickly becoming too hard and anything much below being all but automatic:

+20 points above security skill = unplayable
+10 points above security skill = difficult
-9 to +9 points above or below = normal
-10 below = easy
-20 below = automatic

At least your character with a 90 in Security could open an average lock, in spite of the player having a nervous condition; in turn, a character with 10 Security couldn't open a lock of 90 difficulty, no matter how good the player's reflexes.

Player skill should allow you to beat those "marginal" cases, not do what's outright impossible for the character.

Locks, similar to what was in MW, would be great in small doses. Security SHOULD allow you to spot traps, but failure should be RARE.