Couldnt be certain. What I do know is that I never saw her before nor after the one time she walked into the betting shop with a big wad of twenties. I looked at the form of the horse that won and it had done nothing in its previous three races, hence the 20-1 odds.
I,m talking about decades ago. I guess and I can only guess is that the horse was held back in the previous races and then the trainer/owner knew that it was a good thing for this race. As a result they organised one or more people to pop in last thing at a number of bookies where they were totally unknown and place large bets after the off. That way, the bookies had no time to react and change the odds.
And this is the sort of thing that Joe Public has to contend with.