Interesting observation.
Not really...there isn't necessarily any connection to mornings, and there's nothing predictive about it.
The product will be made even better, and the station is better prepared for whatever might happen...product development and contingency planning are two of the main functions of management, are they not?
I base most of my observations on the basis of the Almighty Dollar™. This is the driving force behind commercial radio, and it's highly unlikely that anything not financially necessary would be airing.
I had been thinking that it's highly unusual to see a co-host on afternoon drive.
No, it's not. It's quite common...even in much smaller markets.
Maybe I'm naive. I don't hear it very often, certainly not in this market. I'm not qualified to make blanket statements, but my opinion has a way of finding its way to the keyboard with regularity.

...if what you read on these boards is any indication.
It's not. Message boards open to everyone are generally full of weirdos, not representative people.
Birds of a feather, you know.

I know who posts on message boards; it's not that different from the people who call a radio station: extremely narrow (and usually biased) slice of the actual audience.