For a time, I would buy keys for CS:GO and different Steam accounts and use a subscription based cheat provider to provide me with ESP/chams on screen. I knew that overwatch/admins would be seeing the demos as the accounts were new Starting from unranked meant you would be under scrutiny already so I adjusted my playstyle.
I learned not to linger around looking at walls. People's movement patterns and decision making eventually became predictable as I reviewed demos or learned in the middle of a match how players have habits and abused that information. I was able to determine when to throw a round away to avoid suspicion and deliberately ensured I had a string of 2/3 bad games every so often so my K/D wasn't insane. I never used any aim assists, spinbots etc., and I always, always communicated with my team through ingame VOIP (not giving cheat calls) and maintained a legit facade.
I went undetected for nearly 2 years and sold hundreds of CS accounts successfully and made a tidy profit doing it. It's another string of the gaming industry that brings in money and it will never go away.
I like to think of it as an online drug war, however insensitive that may seem.