If you haven’t done it yourself, you’ve seen a photo: sledding down the steps at the Philadelphia Museum of Art is one of the city’s best snow day traditions.

It’s also probably illegal.

“I’m almost certain it is illegal, 100 percent,” Philadelphia Police spokesperson Ofc. Derec McLaurin confirmed to Billy Penn in advance of Wednesday’s storm. “As much as I would like to allow it, we can’t.”

Except…they usually do allow it, as evidenced by the pics and videos that blanket social media whenever there’s enough accumulation of the white stuff. The steps are even ranked as the number one best sledding spot in the city by Philly Mag, CBS and Curbed.

McLaurin claims cops have stopped sledders in the past, but could not give an estimate as to how many times it’s happened. “If somebody gets hurt, then we’re on the hook,” he explained.

Or the museum could be on the hook. Since the steps are technically private property — something the police have enforced during protests — use of them for physical activity opens up the PMA to premises liability. There are city, state and federal laws that say, basically: If someone is on your property and gets hurt, you’re liable to get sued. These are sometimes referred to as “slip and fall” lawsuits.

But a spokesperson for the Art Museum brushed off the potential danger.

“Essentially the museum doesn’t really take a position about sledding on the steps,” said PMA chief press officer Joy Deibert. “We encourage people to be safe.”

Stay safe — and watch out for the PPD.

“If somebody comes down those steps, there will be a couple cops down there,” McLaurin told Billy Penn. “Whoever patrols that area will definitely stop it right away.”

If you’re looking for a less illegal sledding spot, you could forgo the steps and check out Parks and Rec’s recommendations. Just know there won’t be city staff out there to help direct you. Per Parks & Rec spokesperson Alain Joinville, since the city sent home non-essential employees on Wednesday, the parks won’t be patrolled.