I just don't get it. Sometimes I walk into someone his house, and when I sneak to their chest, it says: Lockpick.

But, when you kill the person that owns that chest, he doesn't own a key for the chest. How is he going to open the chest then?

I mean, he/she isn't going to lockpick his own chest..

It doesn't mean they have the key on them ~or that it's even in the building.
Who knows what that chest is? Ultimately they are locked for gameplay purposes.

I have a safe that I don't know the combination to.

Seems the reason lockpicks are so easy to find is because no one bothers to have a key for their locked stuff half the time.

they probably have the key stashed under the floor mat or somewhere klepto protagonists won't think to look

Hmmkay..

I like when you find lockpicks inside of a locked chest

Ya thats a real catch 22.if you need lockpicks i know where some are in a locked chest.

I hate when I'm low level and I break 4 lockpicks on an expert level lock and inside I find 2 lockpicks and some gold. I get so pissed off. "Why would you do that?! Who does that?!" It seems like a massive f-you to the thieve's guild.

I have actually found chest keys in some people's homes.

As to why it would be missing in the first place, I am surprised no one has mentioned "The spouse has it and they are not home right now"

They lost the key but they decided to keep the chest anyway.

They keep the chest as a reminder metaphor that every problem has a solution.