The 48-hour rule remains on the books, but some residents said Tuesday that it was rarely enforced. The biggest gamble is to stake out spots with shopping carts from the local Stop & Shop, said Bernie Trager, a lifelong Southie resident, because the store pays someone to go through the neighborhood and retrieve them.

Mr. Trager, 54, digs out other people’s cars after snow for a fee, but does not dare move his own Dodge Ram and rely on a space saver.

“Last year, I shoveled out a spot,” he said. “I came back, and somebody had moved my buckets and taken it. It was my landlady’s daughter. I took that one on the chin, but I’m not taking any more chances.”

For the uninitiated, a local blog, Caught in Southie, helpfully lists the “unofficial rules” for saving parking spots, including: “If you move someone’s space saver and park your car in its place, you have no right to complain about what happens to your car. However, you are allowed to retaliate as long as you don’t get caught.”

The blog also suggests it is safe to ignore the 48-hour rule, saying, “As long as you’re not the last one with a cone out, you’re cool.”

But some residents chafe at neighbors who block off parking spots for weeks or even months.

“If they could,” said Phyllis Simon, 62, “some people would do it until the last piece of slush is melted.”