Over time I have also come to believe that flagging is necessary.
I know there are no financial incentives, but to me that is like a shop owner saying they don't want to clean the shop because it doesn't pay.
It is just part of the cost of doing business.
"there are no financial incentives"
Imagine someone with 500+ followers making a topic every time he finds a cheater, and says "hey guys check what I found, this guy is abusing the system, flag him". Won't he be rewarded for his contribution? XD
There are no direct financial incentives. It takes extra work to earn from it.