Yes all the time.
When they chop my trees, mine my ores, kill my dragons, or in general take my resources, I report them multiple times. I even report the random people in the bank who are alching or crafting or fletching or whatever. And I report all the level 3s near Burthorpe because they'll be up-to-no-good in a matter of time; I report anyone who jumps the wilderness ditch on a non-pvp world. I even made a bot to report random people and set it up at the Great Orb Project area last September when things got out of control.
I hate how it's become something 'everyone does'; it's gotten so casual we don't even try to hide it. And, while I take advantage of it myself, I certainly don't want others to get away from it.
Also, I think I get some sick, perverted joy from schadenfreude. I find that it tastes good. How that's possible, I don't know.
