My opinion is that many people, as evidenced here, simultaneously overestimate their own intelligence while underestimating that of the various forms of law enforcement they may encounter. Not to mention sloppiness in hiding that which you don't want seen, etc. Call it hubris, if you like.

Interestingly, this characterisitic is one of the principal reasons criminals are caught.. they aren't stupid people, but they are arrogant and believe themselves to be intellectually superior to LEOs. Which works fine until it doesn't.