On 04/10/2020 02:17, Wayne Bouchard wrote:
> Groups that have such things I can only presume do not do a good job
> of periodically going through and auditing their IP allocations or, if
> they do, then they don't do a good enough job of cleaning up all the
> details.

It is a long-winded, laborious, thankless task (well, mostly thankless)
and we should be writing software to do it for us. Of course, we all
know how bad everyone is at that, ergo it isn't often done.

On the other hand, perhaps these ISPs are worried that they might be
audited by an RIR?

--
Tom