EDIT: One last point. Probably the best way to detect a mining botnet on your computer is to mine with it. If your hash rate drops then you know something is wrong, be it hardware failure, software failure, or a botnet. There is no way for a botnet owner to steal your hash rate without reducing your hash rate.
lol nice rationalization to mine on any and every computer you ever own or have access to

In case it was not clear I find botnets reprehensible and have nothing to do with them. That is independent of understanding the economics of it.