The only justification I can conceive for something like this is if they are having a lot of missed intermediate scans being reported. They might be making the assumption that people are just tossing packages with bar codes that won't scan into a bag or feeder unscanned so they do not have to bother with them. Since it is very difficult to catch someone doing this without standing over them all night, they may be making the rule of thumb that you are likely to get at least 10 key necessary bar codes a night, so they want to see them. It would also get people into the habit of keying the bar codes, so they would be less likely to avoid it, and also faster at it when they need to.
Often times, when you take a step back and look at the macro level of an operation, you notice stuff like this. Say I am comparing hub A in one state and hub B in another. I notice from reports I can pull, that hub A has a ton of missed intermediate scans in comparison to hub B. I also notice that Hub A has almost no keyed scan entries. I make a logical conclusion and figure people are not bothering with keying bar codes that won't scan. So say I get the appropriate level of mgmnt involved and force hub A to require 10 keyed bar codes per employee per night. The workers in the hub might get ticked, but low and behold, they start keying packages. The number of missed scans in Hub A goes way down.
This is a good example of the sort of thing that can look really silly and wasteful from the micro view of the front lines but winds up in the bigger picture doing what we all should want to do, provide better service to our customers.
Of course, this is just speculation on my part. It could also be caused by some Napoleonic little egoist manger with an axe to grind. That does happen too.