Were you playing on VAC-secured servers? While not perfect, they're pretty good keeping up with the changing landscape of cheats.
That said, taking time for detection to be developed and not wanting to give live feedback to cheat developers are also good explanations for waves.
CSGO is free to play. If you get banned, you only have to register a new Steam account...
The main problem is that VAC can be better but not without elevated privileges aka borderline rootkit and that's not gonna happen