Factual error: In this episode, Max is wrongly convicted of murder in the first degree. However, first degree murder is actually pre-planned murder. As revealed earlier when the Max impostor holds up the bank, his partner compliments him on killing the guard as though it was a spontaneous decision. As the court does not know whether killing the guard was part of the plan, it was most likely that Max would be convicted of second-degree (intentional, but not pre-planned) murder.
Factual error: In several shots in the mile run, Hymie is in the same lane as the Iron Curtain runners, which is illegal and results in disqualification.
Viva Smart - S3-E2
Factual error: When the soldiers fire their rifles at the start of the episode, there should be smoke or muzzle flash at the end of the barrel, but nothing happens.
Closely Watched Planes - S4-E3
Factual error: If there really was a hatch leading into mid-air in the airplane bathroom, instead of being soundless like shown, it would be incredibly loud and Max would have noticed. Also, the sudden pressure change would have sucked him out no matter what he did to stop it.
Maxwell Smart, Private Eye - S3-E5
Factual error: A revolver generally only holds six bullets, but 99's gun fires way more without reloading at any point.