I bet many here in the fan club have watched "It's a Mad, Mad, Mad, Mad World" many times. But, I caught something when I watched a restored edition on DVD my family received this past Christmas.
When they reach the scene out at Joshua Tree area in Southern California, and Jack pulls up in his car, boy did I see a really BIG mistake on Jack. Whoever restored the movie had made his eye color brown, instead of his blue eyes. Seems someone would have caught that error. But, give the movie a look see.
Also see Rochester as a Taxi driver in it as well.