Indeed, you have hit upon one of the significant weaknesses of the ARIN IP registry system - that it relies largely upon the integrity of it's members, in order to properly issue and conserve address space. ARIN is largely based upon the honor system, with one "check" on the potentially dishonest being a general unwilling to be branded an IP address cheat or poor internet citizen. Of course, should one choose to be somewhat less upstanding of an internet citizen, posting one's intentions to do so on NANOG, frequented as it is by various ARIN people, might not be such a good idea. - Daniel Golding
Ralph Doncaster angrily ruminated....
What it tells me is I should have wasted enough space to consume 8 /24s long ago, so I could get a /20 directly from ARIN. I assign IPs to customers very conservatively. Multiple DSL customers with static IPs are put on a shared subnet instead of one subnet per customer. I easily could have used 8 /24's a year ago and still conformed to ARIN rules. At the time I was only using 3 /24's. We recently reached 8 /24s and applied to ARIN a few weeks ago for a /20, but it sounds like the best thing to do is to use IPs in the most inefficient way possible (while still conforming to ARIN policy) in order to quickly qualify for PI space.
-Ralph