As steam has said in this article
https://support.steampowered.com/kb_...DZ-6869#report
As quoted here
This proves that people cannot send movies/videos of u hacking and expecting them to review it.contacting Steam Support to report cheaters is not necessary, nor will Steam Support act on any information provided.
BUT..
But people can report a cheat. As quoted
Please thank me if this was useful.If you know of a new cheat, especially private cheats (ones that aren't on a public website), and can provide the links or the actual binaries, please visit the SteamPowered Forums and PM (private mail) a moderator there and it will be reported to the VAC team.
-schoolies