BGP used to really be the wild west in the early to mid 90's. There were often no upstream filters of any sort. You could announce anything you wanted, accident

BGP used to really be the wild west in the early to mid 90's. There were often no upstream filters of any sort. You could announce anything you wanted, accidentally or otherwise. I worked at an ISP and we were getting tons of spam, all from the same IP block. Another guy decided to announce the spammer's block and black hole it, effectively taking him off the air for at least part of the internet. Eventually, the spammer's ISP called and complained. The other guy said it was a misconfiguration and "fixed" it.