yeah that event had such a huge negative effect on the games economy. i remember selling all the stuff i got to the shop and trying to encourage others to do the same but didnt work
in those games you listed dont u have to be friends with the person to spectate them? that counts as a way to disalow spectators, cause u have control over your friends list.
for spectator mode to exist there has to be an option to disalow sectators, for user privacy. and all hackers would just do that. so it wouldnt help with catching hackers.