The cut off ball is one I think is good but not that secure. Ever wonder about the safety chains? Hook those up to a hitch and skeedaddle....bet that works for most.
For those of you who park in on your own property, here is a pretty darn secure way which I have used many times.
Get out your post hole digger and punch a hole down at least 6 or 8 inches into the ground along the edge of concrete, or in the yard.
Then go buy a bag of ready mix and a decent sized eyebolt.
Fill the hole and set the eyebolt in the cement. Then get a good cable from tractor supply and string it thru a length of plastic hose...this keep the cable off of stuff and make the whole deal look much thicker.
Then just lock the whole thing up the way you want it. When a would be thief sees the rig and the cabling...he will think it is 2 feet thick and way too much trouble to steal.
This is a pretty cheap way to deter crime....keepa yah hands offa my stuff!
I had an uncle who passed a few years ago who lived in Columbus in an apartment complex. But he rented a garage from an old couple who didn't need it for a car and for years he kept his stuff in there.
Then undesireables moved closer and closer and one day, he found the place broken into.
So he fortified the place only to have each effort out done by the guys who want to get stuff the easy way.
Finally he built a solid steal door for the opening and double bolted each end with big locks....
Only a week later he came over to find that they had tied a chain to the bumper and the garage door and pulled the whole door right off of the garage.
He gave up...moved out.
Moral to the story...if they want it badly enough...they will get it no matter what you do.