I ran into this just this past Thursday at SYR. The gate agent was really apologetic and said that the rule had just been put into effect (he definitely wasn't on a power trip). Quite a few of the regular business travelers had a backpack and laptop bag (not roll-aboards, which we're all used to gate-checking on these tiny planes). So I think there's something to this happening recently, but maybe people haven't noticed it being enforced much yet since it just began?