Goofs

Bulldog could not have had Frasier's car towed away from his spot at work and replaced with a wrecked version to prank him when Frasier showed up for work at the beginning of his shift, since Frasier drove to work. The whole beginning scene therefor doesn't make any sense. If Frasier had happened to be leaving work at the end of his shift and found the wrecked car there, that would have given Bulldog the time to switch out the cars. Somebody wasn't thinking when they wrote this.

When Gertrude goes to buy a hot chocolate drink, the cashier tells her it's $32 because "your grandson ordered a bunch of cakes and said it was on you", while pointing to the boy that lives in Niles' building, the boy Gertrude has been fighting with. A cashier would not let a kid have anything without the kid paying for it just on the kid's word that somewhere in the room his grandma is about to come up and pay for it for him. Gertrude cannot legally be made to pay for those cakes.

In the sheet of paper that Gertrude gives the courier man, which is supposed to contain the address of the school, there's no address. It just has the text that he is supposed to say to the boy.

Mrs Moon holds onto piece of bicycle she removed. It is impossible to remove crankshaft and pedals all in one piece, What she was holding was four separate parts that have to be removed separate but not in one piece as shown.

When Frasier storms off from the table at Cafe Nervosa, Steven Anthony Lawrence can be seen standing by the door, obviously waiting for his queue a few moments later.

At the beginning of the episode when Bulldog is describing his prank, he says that he found a "smashed up BMW; same make and model as Frasier's". This is redundant as the term "make" here is referring to the vehicle manufacturer, which is BMW.

Frasier defends himself against Bulldog's prank by saying that he knew the BMW was a fake because his has a bumper sticker that says "I Support Opera and I Vote". Frasier would not put a bumper sticker of any kind anywhere on his car.