Hi Gert,
So option 1, the NCC regularily comes asking ("does anyone in your company know if AS196631 is still in use?"). Option 2, you find a financial incentive to make people return ASNs that are no longer needed, because they find the yearly monetary transfer annoying.
I am convinced that a charge around 50 EUR is a reasonable thing to add - it's low enough that it is not really noticeable for someone who really need a public ASN, as in "takes part of global BGP, has infrastructure, etc", while at the same time annoying enough so you want to get rid of it if you do no longer need the ASN.
Seriously, you're again in discussion similar to 2007-01. How to introduce the fee for numbers? Explain that maintaining a registry of numbers couldn't be for free. Every SS7 code, every license plate, every airport code have a cost. But RIPE NCC already have the registry and RIPE Database is mostly about IP addresses as the most valuable resource. Otherwise we could come to a conclusion that every DB object should cause a fee. At the moment the most fair solution as for me is: charge for the most valuable. Don't charge for person/role/route/aut-num/mntner/poem. -- Kind regards, Sergey Myasoedov