And I'm telling you that such rules exist essentially always (I never heard about an org that didn't have them) it's just that often users are utterly ignorant of their existence until they break them and get punished for it.
Our network had very light rule set because we genuinely didn't care what you did with it as long as you didn't harm the network itself or actively look for unsecure machines until a certain moment when IP rights movement decided we needed to police that for some messed up reason. At which point we had to kick a few hundred people off the net for being power users on the local DC hub. Which was the dumbest decision ever, taken against best judgement of all network admins by higher ups, took out at least one of the network admins with it (he was a power user on the hub apparently) and resulted in massively increased evening load when everyone suddenly started to get their warez and porn from outside the network instead of inside.
The network that was never congested suddenly got super congested every evening. Thanks to dumbasses high up. Guess who users thought was to blame? Yeah, network administration. The people who made the rules got away with it clean.
I was a network admin for university campus while studying there for several years. I know what I'm talking about. Not sure if you do.