Also back in the olden days of ring side bookies at the race tracks, it was illegal to transmit information "off-track". It didn't stop people inventing system

Also back in the olden days of ring side bookies at the race tracks, it was illegal to transmit information "off-track". It didn't stop people inventing systems to do it though. Clever use of very old mobile phones which used acoustics to transmit bookies markets off-track, and then used for wagering purposes. It's been around for a while. These day's it's just not necessary. You have the William Hills, the Ladbrokes, the Tom Waterhouses, the various on-line bookies, all providing easily scrape-able data sources.