I'd be more than happy to see this, with the added caveat that anyone
that returned address space to ARIN that was subsequently marked as
'contaminated', should undergo a review process when attempting to
obtain new address space. Charge them for the review process
Anyone that intentionally uses address space in a manner that they
know will cause it to become contaminated should be denied on any
further address space requests.
Another option, is to hit them where it matters. Assign fines and fees
for churning address space and returning it as contaminated. Set the
fee's on a sliding scale based on the amount of contamination and churn.
the more contamination, the higher the fee.
It would be problematic in some dimensions, but it seems that perhaps
allowing them to return space in exchange for a larger block is part of
the problem, and maybe part of the answer would be to make them retain
the block and only allocate an additional block. Route table growth and
all that, of course. An alternative could be to delegate them a larger
"contaminated" block and allow them to incur the expense of cleaning it
* And I say that kind of tongue-in-cheek, since I don't really believe it
to be easy to clean up a block once it is contaminated, due to the sheer
number of local blocks, etc., which may exist.