blizzard is much more cheat enforcing. they can detect any and all cheats, there is no "undetectable cheat" on battle.net for 2 reasons
1) people will snitch on you
2) they have paid profressionals WATCHING the servers looking for some idiot whos hacking.
(yea i go to blizzard tech support, i even have gotten to know a moderator pretty good whos name is Alex, i asked him about cheats, believe me, you will be banned, and theres no unbanning.)
sierra on the other hand, will ban the cheats they can detect, ive reported hackers with demos and screenshots, they do nothing. the only way is to report them to the admin of the server, or join a different one.
btw, hackers in my book are neutral, i have to admit, ive hacked before, bought a year ago. it kinda sucks. most people think because they have no skills, i was completely bored, and i was in cal and ogl. i believe i had skills. not all people hack to be good, they hack because theyre bored (sometimes)