there was a convar in the game for 6+ years that let you see particles in the fog of war; 99% of cheats forced this convar on. source lets you request CVars from the client and the value, so they simply did that. it has nothing to do with reading memory, but rather writing memory to allow you to see particles
if dota is anything like CS:GO, then most CVar-editing cheats are done by hooking the underlying functions instead of just forcing them. I distinctly remember the word on the street a few years ago being that manually writing to CVars was Dangerous Stuff To Be Messing With.
there was a convar in the game for 6+ years that let you see particles in the fog of war; 99% of cheats forced this convar on. source lets you request CVars from the client and the value, so they simply did that.
to be clear, this was not a honeypot, but they claimed it to be
Hmm, well I wouldn't permaban people for using a known... built in setting, even if it gives an unfair advantage.
_edit_
To whoever downvoted me later - I would consider it a bug if it was user settable without cheats. Similarly you could see trough smokes in CS for a long time by changing some video settings. You don't (usually) ban people for bugs.
Ah, yeah sounds plausible then. I somehow don't buy the guard page/hw breakpoint explanations. This also lines up with "[information] that wasn't visible during normal gameplay".