There is no way the gambling sites will even know.
I don't know much about this, but I suspect some casinos which share details with each other through their providers, like SOFTSWISS, which offers casino and sport book services to of lot of casinos, could share details with clients. That's just my guess. And this statement I will quote below makes me believe more about that.
Edit: Additionally, don't lie and say you were going to bet on World Cup.100% of your bets on Betcoin were on table tennis, including your 17 rejected bets. And so far the information we have shows that 100% of your bets on every other site were on table tennis, as well.
You don't need a bookmaker representative to answer this question. It is not a crime but it will likely go against the terms and conditions that you agree to follow when signing up with any particular sportsbook. It is not against the law in pretty much every jurisdiction, but it will likely lead you to being banned - but that is the extend of the enforcement they can take. Be careful because if you have additional funds in your account then you might end up having to go through a long and drawn out process if they freeze it while your account is "under investigation" for breaking the terms. Every bookmaker is going to actively discourage and proactively try to detect (by best guess only) when you are trying to take advantage of them through this kind of matched betting.
More like it, there is not a general law set up for all sports betting platforms, but it could as well land someone in trouble. What I'm asking is a bit different from what they refer to arbitrary betting, which I consider an unfair rule against bettors trying to explore.