Don’t go trying to smuggle a large bucket of popcorn into a Cinemark theater this weekend, because the theater chain is banning backpacks and large bags from its theaters nationwide — including 15 locations in Utah.

A new policy, “to enhance the safety and security of our guests and employees,” goes into effect Thursday at the Cinemark chain, barring any bag bigger than 12 inches by 12 inches by 6 inches. That means most backpacks and large purses will not be allowed in the auditoriums.

Cinemark does have an exemption for medical-equipment or diaper bags. Theaters will not provide lockers or check-in areas for bags that are too large to be taken inside.

James Bennett, a high-school teacher in Salt Lake City, approves of the ban.

“Outside of transporting medical equipment, the only reason I can see for a huge bag — other than something truly nefarious — would be to smuggle in food,” Bennett said. “I’ve never understood that Utahns, and especially parents with children, would send the message to their kids that stealing from the profits of a movie theater is acceptable.”

Safety concerns — particularly in the wake of mass shootings, like the theater shooting in Aurora, Colo., in July 2012 that killed 12 moviegoers — have prompted theaters and other venues to tighten their bag policies.

• The Utah-based Megaplex Theatres chain, with 15 locations across Utah, bans large bags and backpacks, and will sometimes search smaller bags. Megaplex locations also post signs on the doors banning weapons.

(Sean P. Means | The Salt Lake Tribune) A notice on a door at the Megaplex Jordan Commons in Sandy states the movie theater chain's policy against weapons on the premises.

• The University of Utah is phasing in a clear-bag policy at Rice-Eccles Stadium and the Huntsman Center this fall. When the Utes’ football season starts, fans will be allowed only clear plastic bags, 12 inches by 12 inches by 6 inches, into the stadium.

• LaVell Edwards Stadium at Brigham Young University in Provo allows bags smaller than 12 inches by 12 inches by 12 inches, subject to inspection. No outside food or drink, even bottled water, is allowed in the stadium.

• Vivint Smart Home Arena, the downtown Salt Lake City arena that the NBA’s Utah Jazz call home, prohibits oversized bags and backpacks. Purses, diaper bags and small handbags are allowed, but are subject to search. The Viv also has metal detectors at its entrances.

• Rio Tinto Stadium in Sandy, where Major League Soccer’s Real Salt Lake plays, limits bags to 14 inches by 14 inches by 6 inches. They are also subject to search.

Cinemark, based in Plano, Texas, has 15 locations in Utah, under the Cinemark and Century brands: Salt Lake City (Sugar House), South Salt Lake, West Bountiful, West Valley City, West Jordan, Farmington, Sandy (Century Union Heights and Cinemark Movies 9), Draper, Layton, Ogden, American Fork, Orem, Provo and Spanish Fork.