Blatant Market manipulation in these US markets

Has anybody noticed the extremely large (nearly 2.5k) sat there to lay, up to a full point lower than the current market price of the favourite, in some of these US markets?

The money is obviously there to prop up the price to faciltate pre race trading.

If the price drops to within  a few ticks, the money moves a few ticks lower.

With the average pre race traded very low, they are banking on nobody wanting to "invest" such large amounts - so they continually get away with it...