Chicago (where I live) just had a fairly large blizzard (20 or so inches or about 51 cm) . This, as you might imagine, causes problems for transportation. Despite a robust system of public transportation, Chicago is a car city. When it snows, these cars–often parked on the streets, get buried beneath mountains of plowed snow. This creates a unique sort of property problem.
It goes like this. You spend four hours liberating your car from its snow tomb, or creating a parking spot where before there was just piled snow, so you conclude that on account of your mixing your labor with that parking spot, that you can call "dibs" on it; you worked it, it's yours.
Having just liberated my own vehicle from a snow tomb, I have a bit of sympathy for this approach. Nonetheless, I'd prefer an honor system. A student of mine this morning put it like this: if you are looking for parking, then you have yourself worked to free your car from a spot, which is now open. Not a bad idea, though it needs some filling out.
Another student forwarded me the following argument against dibs (from Time Out Chicago):
Why is dibs a bad thing? While snowfall can be a magical thing, snow doesn't magically turn public spaces into private property. It's a very un-Chicagolike tradition: When snow falls, all of a sudden neighbors become vehement and territorial.
If someone puts in the effort to shovel a spot, they don't deserve a claim on that space? If you push someone's car out of the snow, you don't say you own their car, do you? I also question how much sweat people put in. The snow that fell [in mid-December] was not enough that people had to dig their cars out, yet there are chairs all over.
Is there evidence that dibs is a problem? There's a thinly veiled threat of violence associated with dibs. People who've violated dibs have gotten their cars keyed. I once heard a story about someone breaking the back window of someone's car and putting a hose in there and turning it on.
Doesn't tradition carry some weight? Not all traditions are good. Political corruption is another Chicago tradition.
Even though I'm leaning against dibs, these are really terrible reasons. The second one, especially. The principle works on the Lockean (or something like it) theory of property. If you mix your labor with it, you've earned it. In this case you earn it temporarily, and no, it's not like claiming someone's car is yours.
**Update
on dibs from the New York, I mean, Huffington Post.