If I was trying to find evidence of past posting I would focus more on speed horses that were bet heavily but missed the beak.
Did they drift up on the last flash more often than some control group?
Did they drift in the opposite direction from what the Will Pays suggested?
Unless you think "The Russians" are hacking into our pools and actually changing bets and time stamps (in between rigging our elections
), it's more likely someone has the ability to past post for just long enough to see the start and first 70 yards or so and then can either enter or cancel a bet depending on that incremental information.
There's a history of that kind of thing in harness racing and I personally experienced it on a new site about 10-12 years ago. I reported it to the site and it was fixed.
The concern is that there are obviously some brilliant people out there capable of all sorts of hacks, there's a lot of money at stake, and I suspect the security for our antiquated betting systems is probably not at the level it should be. So people are justifiably going to be suspicious even when what they are observing could have an easy and satisfactory explanation. Someone with a lot of extra time on their hands should actually study it.