Best sci-fi TV stupidity of 1966

The Revenge of Robin Hood - S1-E16

Stupidity: The Time Tunnel technicians send a homing beacon to the dungeon to help Tony and Doug, but through the episode nobody notices the well-lit, futuristic-looking object propped against the dungeon wall next to the door.

Scott215

The Enemy Within - S1-E6

Stupidity: McCoy could have found out which one was the fake Kirk by just giving him a medical scan - the fake Kirk drank brandy. But then again, he could have just smelled his breath.

hifijohn