I'd like to second Serge's sentiment, RFG catches a good deal of abuse for his contributions, which we have all seen on this and other lists. What the continued findings indicate is a need for IANA and the RIRs to adapt to a new stage in the resource issuance and governance lifecycle. Since this is by definition a working group, would it make sense to establish some metrics to quantify the perceived impact of this phenomenon on abuse?
If we establish a process to collect these observations of either "abandoned" resources, prefixes or ASNs, which then re-appear mysteriously or in the case of an ASN start routing space that is unexpectedly, "hijack", we can take a step as a community to quantify the phenomenon?
Note: This is specifically not an internet policing function as much as a neighborhood watch effort to help inform the governing bodies / policy ... etc. Right now from responses it seems like defacto this weight has been put onto the shoulder of Spamhaus vs. having a working group work on a solution.
If this is of interest I'm happy to write up a proposal and or work with the chairs to see if this is something that is seen as constructive. Also if this doesn't fit into the anti-abuse working group ... where does it fit?