Elise:
Bill's question, "Are each of the regionals who get a CIDR block encouraged to either report back assignments..." is one that is raised every so often. Yes, regionals who get CIDR blocks are encouraged/expected to report reassignments of the block to the InterNic. This is one of the fundamental tenants of the distributed allocation procedure.
Is there some confusion about registering reassignments of allocations with the InterNic?
This just ain't good enough. For years already we have problems with stale network numbers (or silent or whatever you call them), for example. There is and has not been any incentive to communicate with "the NIC" once you have a network number. This will be much worsened with CIDR allocations unless there is a clearly defined process in place. I believe a good way to do this is to reverify network number information annually. Could be spread all over the year, so not tens of thousands of network numbers have to be processed within a few days. People need to act like network numbers are a common good, and not hogable personal property. People should loose network numbers, unless they participate in the process. CIDR is a funny thing here, as on the one hand it makes matters worse due to the assignment of blocks, while on the other hand and from a certain point of view it makes things less severe, as certain things matter less if there is a hierarchical addressing structure in place. Hans-Werner