The lack of care regarding source engine netcode extends to every part of the source engine, including Valve Anti-cheat.
The anti-cheat is trivial to reverse (several PUBLIC bypasses have existed for years on github, with zero patch), the engine source has been leaked, reverse engineered, and fiddled with by thousands of 14 year old kids. It is pathetically easy to bypass, for example, by changing a single byte in memory you can see through walls, see enemy money, etc. See this video I found about how miserably broken it is: https://files.catbox.moe/8e3bxz.mp4
It is in my opinion the greatest loss to gaming that a classic, legendary game like Counter-strike got completely ruined by lack of care by a company that profits millions off of the case unboxings.