Hello Marius,
Let me motivate: Amprgw DNS entries are only relevant for connected subnets. There is no public accessible tunnelled 44 network without having a portal entry. If there is no such entry, the tunnels would not work. BGP announced 44 subnets are well known, and can be easily excepted from the delete process. All other existing dns entries associated with a 44 address, if they exist, will be not be impacted in any way, since they are isolated, and the dns services at amprgw are not used by them.
My speicific issue here is that my local AMPR coordinator recently told me that unless all my IP addresses had a DNS entry, I risked loosing my allocations. I think this is a policy that *he* is setting himself (not a global AMPR policy) and though I don't agree with his view, I obliged to give him ~1024 hostnames to fill things out. If other AMPR coordinators have similar approaches, then DNS entries mean everything to the IP allocation be it a subnet or a /32.
--David KI6ZHD