Not something that many HN posters will be familiar with, but if you're a holder of significant pieces of ARIN or RIPE IP space, you'll inevitably be approached by a number of suspicious looking companies that want to "rent" your ipv4 space (by the /24 block) for VPN/proxy usage.

The end result if you actually fall for their bullshit is that your IP space will be listed in every RBL until the end of time, and will have a bottom 5% rank in every IP space reputation/antifraud system until the heat death of the universe.

Every time I've been approached by these clowns, I've spent a cursory 3 to 5 minutes trying to find an actual business behind it (names of real humans, street address that isn't just a mailbox, location of real ISP infrastructure equipment at some real IX points) and failed to find anything resembling a legitimate ISP.