Norm says Gary wouldn't run him a tab. However in season ten he stated he had a tab over at Gary's Olde Towne Tavern.
Even though the beginning of this episode takes place hours after the previous season's finale, Rebecca's hair is noticeably shorter and lighter.
Although somewhat hidden by a small rug, a cord can be seen running to the trash can that Rebecca dumps her cigarette butt into, presumably to ignite the contents.
As the employees and regular customers of Cheers examine the fire debris- and then later begin to clean it up- none of them show any signs of soot marks, even though they lean against clearly burned parts of the bar.
Fire Marshal Dobbins would not be at a fire scene in full dress uniform.
When Sam is trying to figure out ways to finance the refurbishing of his bar, it never occurs to him that he could sell the boat Norm bought for him the previous season.