If they're using them for internal networks, they'll (probably) work just like they did before. It's likely many folks are using these as like private RFC-1918 addresses.
If they are private, which they could be, I wonder why they are showing up in public on there... Also, ripe.net has ripe stats... Checked a few of the ranges and seen people other than the dod and these lads announcing the range...
Anyone can put an address in their DNS records, whether it's "theirs" or not. I have several records with 192.168.0.0/16 IPs. The DNS can be seen publicly but obviously they don't route. It's the same thing.
Other folks are definitely using those DoD addresses. For example, I see a bunch being announced by AS23352 / Server Central: https://bgp.he.net/AS23352#_prefixes
