I just read Gabriel W.'s post on https://brilliant.org/discussions/thread/staff-post-announcement-price-increases-on-points-/
It talks about cheating through math help websites. And if you search google, people have literally copy pasted problems from Brilliant into some forums and have got right answers for that.
I can understand incentives for people to cheat in school, but why would anyone cheat on free websites like brilliant? It is my belief that this is happening due to the prizes on the point exchange. People are these things really that important, or are maths and physics more important?
I vouch for changes or elimination of point exchange or maybe something else you might suggest.