> There are few enough addresses (even in the 10.0.0.0/8 private range) that subnets have to be manually preallocated to avoid conflicts

I hate to be that guy, but it's 2021 and we should start deploying stuff on ivp6 networks to avoid this kind of problems (beside other kind of problems)...

edit: ok I just saw the PS about ipv6 and Azure... sorry.