SFO Ground Controller reported that taxiway restrictions were not properly complied with.

Narrative

I was training a developmental on Ground Control with a restriction on widebodies exiting the runway. The restriction was no widebodies on Taxiway D between Runway 28L and Taxiway B. A 767 had exited earlier and I told Local they can't be there. A while later...here we go again with a B747 exiting at D. I interrupted the conversation between Local; Coordinator & TMU; and said D is restricted. Local shrugged and said oh well. A mobile vehicle called and asked if we still showed the restriction. My Trainee said yes. A few minutes later Airport Operations called the CIC about it. The CIC and the rest joked and laughed about it. When the Supervisor came up and relieved the CIC; he was not told about it. When we were relieved I told the Supervisor so he would not be blindsided. Team work only works if people want to be a team. I don't care who you are; I will warn you about a situation. Maybe my Trainee and I should have said STOP to the B747 and coordinated with Local and the city. I don't know as the B747 was already on D calling us. Traffic was on a 1 1/2 mile final to Runway 28L.