What's the other 1%? For eg., in Dota 2, if I create a private lobby, would that allow the mod vpk files? Or only for local bot matches? Or some other more involved scenario?
Not sure about Dota specifically but for e.g. TF2 any non-Valve-server game had pure off by default. That does mean bot matches or private lobbies. You could hop into a community server and run your mods fine right now if you wanted.