A a couple of more red flags are the "winning" slots method also sold on the website, as well as the G-14 method being authored by a guy named Gus.
Interestingly enough, they also sell the fine hardcover book "Payday at the Races", which I believe I added to my collection some 20+ years ago from a garage sale for 25 cents. Published in the late 1950s I believe, it can be yours for a paltry $8. One tip IIRC is trusting only older geldings for consistency - classic.