Like mentioned in the article, often times the material is very obviously suspicious and banks probably know this and still turn a blind eye to it because these borrowers are low risk and much less sensitive to the high/rising interest rates of today...
These aren't purely private transactions. If HSBC Canada fails, Ottawa is on the hook. The defrauded party here is the public. (And possibly the bank's lenders and shareholders.)
I think what many people are imagining is the subprime mortgage situation of yore. But in this case, a lot of the "fraud" is the result of knock on effects from capital controls in the PRC. Many (new and aspiring immigrants) have capital from sales of their property in China, but due to capital controls, cannot get it out quickly. They have to do it in $50k/year chunks.
Usually a loan or mortgage is the solution for this, but those depend on _income_ rather than _wealth_, so normally these people can't take out as much as they need to, even though they could easily back actual value of the mortgage. So there's a little collusion between banks and mortgage brokers to get in on this market gap (probably more so now that interest rates are high, which these borrowers are much less sensitive to).
Of course, there are risks, but those risks are tied to more geopolitical circumstances and less market-driven, and apparently banks are more willing to take their chances on that.
If BC property is being fraudulently leveraged against Chinese real estate, opaque decisions by the ccp can dramatically impact default rate for Canadian loans.
No market actor would expect that in a non-fraud based market. Instead a transparent pricing of Chinese assets would show them as much less valuable on a risk adjusted basis than their book wealth value. Especially compared to western income or equivalent wealth.