Now very briefly AFAIR, there were signaling buttons on the top of the stands, though not shown in the picture. My impression was they were going to try something like "jump-in" questions, but I never did see these lights come into use at all. Anyone know?
I’ve wondered that, too, and about the narrow piece added to the bottom of face-off stand on Dawson Family Feud.
That FF piece you're referring to, I believe, was where they stored signaling buttons for the face-off, in case one contestant didn't have the strength/ability to walk up to the stand. I'd first seen it on a special "Celebrity" edition featuring the cast of Gilligan's Island. Here is an episode featuring the system:
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You'll see it utilized around 11 minutes into the episode. The buttons were wired, and if conditions were necessary on current series, they'd probably be wireless.