I actually know a guy like that; he sold cocaine to a uniformed policeman, and he’s serving 40 years in a state prison. He was not originally a dimwad. The coke did that to him.
That’s when I decided never again to touch cocaine.
I look at it this way: would we rather have smart criminals? 
We do; being smart they don’t get caught.
I was once in court as a character reference.
(Yeah, the defendant was truly desperate )
While I was waiting to testify, I watched the following:
Judge: So how did the state trooper find your marijuana?
Dimwitted Defendant: Well, he stopped to help me change my tire and he was so nice, when he asked me if I had any pot, I got my stash out.
Judge: So you just handed him your marijuana? He didn’t see it in your van?
DD: Yeah, I had it hidden but I thought he just wanted to smoke a joint with me.
Courtroom erupts in laughter.
Here’s another one but at least in this case she may not have known her visitor’s were police officers - they were in plain clothes.
Too many people must have listened to the young George Carlin’s Sixties monologue “Shoot,” which was all about the word shit, “It’s a nice word. A friendly word.” He imagined a clueless plainclothes cop who never learned the street slang for pot. Some guy rolls up, “Hey man, wanna buy some shit?” “Where did you get this… shit?” “Well, we brought it back from Cambodia in a guitar, we baked some into brownies, and we’re sellin’ the rest.”“You want some papers with that?” “Yes, better give me a roll or two.”