Gun control advocates in Tacoma, Wash., are thinking inside the box -- literally -- with a controversial proposal to set up a gun "drop box" to encourage residents to turn in firearms, no questions asked.

The city of 203,000 has similar collection boxes for drugs, and officials say a secure, steel box can help get guns off the streets without subjecting nervous citizens to police interaction.

"The main intent and goal is just to get these weapons off the streets," Tacoma Police Chief Don Ramsdell told the The News Tribune, stressing that the program is still in its planning stages.

“Are we really expecting these people to walk down the street to this dropbox, with the gun tucked in their shorts, and drop it off? It doesn’t seem to me to be a thought-out process as off right now.”

- Sgt. Jim Barrett, the president of the Tacoma Police Union

Dubious critics say a box full of guns could prove tempting to criminals -- and that's if people actually took the city up on the offer.

"In other news: New Gun store for criminals opens in Tacoma called: The Drop Box," one person tweeted.

Tacoma Police Union President Sgt. Jim Barrett doubts the boxes will get much use.

"Are we really expecting these people to walk down the street to this drop box, with the gun tucked in their shorts, and drop it off?” he asked. "It doesn't seem to me to be a thought-out process as of right now."

A host on KIRO's "Tom and Curley Show" agreed.

"We have this need in the community to have a place where people can innocently drop guns in boxes," one host said. "Can you imagine someone walking up to the box -- right? -- look around and the put the gun in there? Can you believe anyone would do that?"

While the drug boxes are free-standing, one police official theorized that guns could be passed through a slot on the side of a building and deposited in an inaccessible area. Melissa Cordeiro, a city gang reduction project coordinator, told KIRO Radio that the guns could be placed into the box and at some point "law enforcement would swing by and pick it up out of the drop box."

The proposal follows similar attempts by cities to get illegal guns off the streets, including gun buyback programs. Cities across the country have offered residents cash,  bikes and even jobs in return for handing over a firearm.

George Mason University economics professor Alex Tabarrok said those programs have been proven ineffective, and he predicted the same result for a drop box scheme. Anyone in the port city who wants to get rid of a gun discreetly, Taborrok said, has an easy option: toss it in Puget Sound. 

City leaders out to reduce the number of guns on the streets largely have their hands tied, said Taborrok. Any historic gun decline in a city would only come after new gun-control policies from Washington, D.C. He said city mayors' best tool to keep crime down in a city is to increase police patrol.

"Any funds you'd use in programs like these buybacks would be much better served by adding an additional police officer," he said.

In November, Washington state passed new gun laws that call for universal background checks for all sales, including those made online or at gun shows. The measure has exceptions for emergency gun transfers concerning personal safety, gifts between family members, antiques and loans for hunting.

A federal judge in May threw out a lawsuit challenging parts of the new law that expands background checks on gun transfers, saying gun-rights activists couldn’t challenge it because they aren’t being prosecuted for violating it.

The Associated Press contributed to this report.

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Edmund DeMarche is a news editor for FoxNews.com. Follow him on Twitter @EDeMarche.