Well it's not going to cause a "short" because it doesn't have live 240V on the pins in that plug handle all the time while it's unplugged. But that's still a really bad idea because it's going to get a bunch of dirt and gunk in the pin holes in that plug, and then with dirty connections in there, it's going to start not making good metal-to-metal connection when you plug it into your car, with higher resistance and heat and probably the car starting to report charging errors or having to lower the current because of detecting those dangerous heat problems.
I would definitely find some place to hang it back up. Walking back to just drape it over the body of the wall connector doesn't seem that bad to me.