I think they have failed to understand pay out ... laying at high odds and backing at lower odds is red all around (guaranteed loss).
And just because the horse had traded at 2.00 it does not mean it has won.
lay $2 @ 50 = $98 payout for when lay wins
back $50 @ 2.00 = $50 win .. still $48 loss ...
should the horse trade at 2.00 and not go on to win the race ... $50 loss on the back and $2 win on the lay .. -$48