Miguel,
I first observed similar behavior to what you are describing in back to back hunting seasons about 5 years ago and I posted about it here. It had to do with maternal does allowing yearlings to apparently act as "decoys" and I observed it too often to not believe that is exactly what was happening. I think it's simply their learned reaction to being legally baited and hunted from tree stands. Deer used to never look up either! Not so long ago, any yearling so anxious as to try to get ahead of its mother to rush into a place she associates with danger would surely have received a swift kick. Now yearlings coming in first is not at all unusual. I've watched "wind sprints" across my shooting lanes, knowing full well mommna is 50-75 yds behind my completely camoflaged stand in a tree I've never hunted before. I can accept that it was easy to let jr.'s youthful exuberance take over(just don't kick him upside the head). I'm just completely stunned at how she trained him to do the wind sprints before "go live"! What I observed was not merely playful behavior, it was precisely choreographed movement directly under my stand to get me to betray my presence. The only time the yearling stopped and rested was when it was safely behind brush. This was...dare I say it....teamwork!
P.S. The last episode turned out poorly for jr., I learned to snap shoot from a sitting position and drilled him the second she blew. I cannot abide conspiracy!