A little history on that...there weren't really server-wide rules that map. It was a temporary map, they were experimenting with the Factions mod. Each faction made their own rules, and they were enforced by the faction leaders. My faction had disbanded so I built out in a desert. This jerk, buckaroo, stole all my stuff and left signs taunting me. He also did that to a number of people. I hunted him down to his underground lair in his faction's territory, and joined them without reading their rules. The leader of that faction happened to be an admin. I wandered around their territory, scouted out buck's primitive cave, stole some TNT from his brilliantly labeled "Stolen Loot" chest, and blew everything up.
Was it right? No, and I fully understand that. I took my ban without complaint, and I still play on SL.net. I don't make it a habit of breaking rules and griefing griefers, but you wanted to know about any previous bans I've received.