Nobody who's less than a few years old is going to have the ability to consign 10+ horses to a private auction, though.
True, but if there's incentive to auction several horses at a time rather than just sell them off gradually over the course of a year, then there are more horses available to new members, in theory.
Also...I /could/ see two very bored people selling the same horse back and forth for hours to get the points. I'd suggest putting in a check to avoid that sort of thing, if we can.
As Jason said, this is taken care of with the 3-use/6-month waiting period for selling horses.
And rewarding for selling not buying, whilst it might get another horse or two up for sale...newbies aren't going to be selling horses. What worries me is that this could help the 'rich get richer'.
Selling and buying are both rewarded...buying less so because most people buy many more horses than they sell. (I did originally have it setup so that they got equal points, but then some stables had over 1,000 points, so I brought it down a bit.)
Also, no one says you have to redeem your points. If you happen to have the stall space, then you can get an extra horse (assuming you have enough points, obviously). Otherwise, you can just get a discount on a breeding, or some extra cash to help out with taxes and such.
Given that the rich are already pretty damn rich (Jase has earned over 20 million this year in race winnings alone), I'm not sure that adding this in is going to make rich stables any richer. (I know I, for one, will likely be too lazy to redeem points for cash, though I may redeem them for free breedings or a new horse every few years.)