Never noticed thi thread till now. I will pipe in my two cents worth.
This is such a grey area and Revenue Canada has pushed about 10 cases hard. Won 1/2 and lost 1/2 Big one was guys who did Sport Select full time and won big. They are the reason there were limits put down as to how much you could gamble at one location of sports select. These guys were raking in millions. Revenue Canada went after them and lost. The cases they seem to be winning are organized crime were there is sports betting and bookies.
I used to Bomus Hunt huge and was part of the secret bonus hunting group fatbonus and the new one that broke apart. For three years I was making more bonus hunting than my regular job. I spoke directly to revenue canada and an accountant and both said I did not have to pay tax. At one point I was looking at going fulltime and my accountant advised me not to pay taxes. Keep my deposits under $5000 and utulize my neteller instabank card alot( I realize this is not possible now) He laso suggested I take 20% of my winnings and set aside in investments. His reasoning was if they ever did come after you than you have some back up. Though the main argument in all cases is if you dont tax the guy that makes 10 million winning the lottoery how can you tax someone making $100,000 at poker.
Remember this though CDN Tax Law is different than stnadrad Law. Guilty till proven innocent.
Bottom line is if you have a regular job and play your safe. If you play full time you are in a grey area. I have never paid tax and my banker knew were the cash was coming from and many deposits over $5000 but never any problems.
I miss those bonus hunting days