Principal Skinner punished all the students, when Bart was the only one who did anything wrong. Therefore, he should have punished Bart and the other student should have been free from all punishment.
When Bart and the elderly board the boat, the Sea Captain says "Not a looker in the bunch." Later on when Mr Burns' yacht crashes into the boat, Lisa asks how could the Sea Captain not see the yacht to which he proclaims "Two Glass eyes", this being the case, he wouldn't be able to of seen the elderly to begin with. Also, he can see in later episodes.
After the Indian man breaks the window, the Old Jewish Man comes to yell at him. Just a second later, he is back at his chair.
The Springfield Tire Fire has a sign saying "Est. 1989", yet in Flaming Moe's it is shown that the Tire Fire started in 1966.