Here is the Pro Line case: http://decision.tcc-cci.gc.ca/en/200...006tcc680.html
The CRA lost the case because they could not prove that the defendants did anything to minimize risk and the defendents emphasized that Pro line is a lottery and not sports betting and thus there could never be a reasonable expectation of profit and there is a public perception that lotteries are tax free that the courts did not want to counter.
The CRA uses the Net Worth Analysis.
It means they take your net worth as available from records, add estimated living expenses and deduct out your known (declared) income. If there is any difference, then they can prove you have undeclared income.
Public records tell them if you have homes, vehicles or real property. You would have to turn over bank statements. They can also interview neighbours, look at your credit card statements, border crossing records, etc.
Since there are something like 60 people in Canada available to do this, it has to be big bucks evaded before they bother.