My guess is that these bets you are seeing are on the dogs?
If they are I can assure you that they are "bot" bets and even if you could
see them and place any bet in front they will simply jump ahead of you
again. That is until the prices become either untradeable or generous to a
fault, in which case they will stop.
Hope this helps - Michael
P.S. This is the main reason I have personally eased up on greyhounds.