Wonder how many people still get hooked by these, though...

What stops online gambling conglomerates from creating terms that say “you can’t hedge your promotional money bet on another gambling site” and cooperate with other sites to enforce it? Casinos already happily cooperate with each other to ban card counters from blackjack

Also for anyone confused by the article, the Wikipedia for matched betting is much better at explaining all this https://en.m.wikipedia.org/wiki/Matched_betting