Whether or not Valve Anti-Cheat System works, I believe its existence has reduced the number of players who assume every good player is hacking. In the old days (0.6 maybe?), chat was filled with hack accusations on death. These days, it seems like it is said less frequently, and mostly in jest.

Then again, sometimes it is very hard to tell if someone is wallhacking or just good/lucky, so I could just have a false sense of security on the issue. However, this sense (false or not) is enough to eliminate any frustration on death and just assume I need to get better.