I've often wondered if it is convenience rather than IQ that is the limiting factor for this. If I approach a bin with two hands full of garbage, how much time am I going to spend using half a hand to open an elaborate lock mechanism? Not much.
If you won’t spend the requisite time to properly dispose of your refuse, even if mildly inconvenient, then you don’t belong in our parks.
In addition, if someone reaches the "I need two hands to open this and both hands are full" stage and can not figure out a solution, it would appear that IQ is still the limiting factor.
Not belonging in the parks and not being in the parks are two different things, though.