Not so long ago, D.C. cabbies followed strict procedures when it came to their licenses: They had to be displayed on the passenger-side sun visors of their vehicles in regulation plastic sleeves—which, for many years, were manufactured by inmates at Lorton Correctional Complex and distributed at the offices of the D.C. Taxicab Commission.

Protocol has slipped.

Philip Lebet, who has held a D.C. hack license since 1982, doesn’t drive a cab much anymore—he is currently the corporate secretary for Diamond Cab Company. When he does, his face is right there on his right-side sun visor, in a Lorton-made sleeve, though the piece of plastic is held in place with rubber bands, since the contraption’s straps fell off long ago.

He could just buy a new license holder, but Lebet says they’ve become hard to find since Lorton closed in 2001. There are places that sell versions of the accessory, including National Cab, a former cab company turned supply store that has been ordering overseas-manufactured license holders since Lorton closed. Some cabbies get them there.

But using one of the newer models could be breaking city rules. D.C. Municipal Regulations stipulate where and in what a driver’s “hack face” should be displayed—specifically, “attached to the right sun visor so as to be visible to any passenger in the vehicle” and inside “a bracket or receptacle of a type approved by the Commission.”

Lebet knows the one he has is approved by the commission, because the commission sold it to him. “To my knowledge, we can’t use any other ones,” he says. “If we can, it’s news to me.”

Causton Toney, chairperson of the Taxicab Commission, says his organization doesn’t maintain a list of approved picture sleeves these days. “We don’t have specs—which would be nice to do—on the size of the envelope, the transparency of the envelope, the means by which it would be affixed to the visor,” he says.

Toney says the primary concern is that licenses be visible to passengers, not to nitpick over how they are displayed, but Lebet plans to hold on to his old plastic envelope until the matter is resolved. “These sort of things are judgment calls,” he says. “Which means that there is potential for abuse.”