A 6RD allocation should be 100% 6RD and no other use of it should be allowed, so that it can easily be returned once the 6RD deployment is no longer in use. I agree regarding allocations that were requested for use with 6RD. However, LIR/ISP requesting space from "their own" /29 should not require documentation when used for 6RD. For some reason, ISPs tend to deploy 6RD inside "their own" /29 rather than requesting a new /2x.
That, or, roll native. ;) I like the rolling native part :) When it comes to mobile network, we might be stuck to transition technologies forever(tm). There will be parts of the network that will never be LTE only, like strange sensors in some (hopefully not mission critical) infrastructure and things like that. So chances are, when looking at mobile networks, that a 6RD deployment will never be returned. :(
regards. danrl -- Dan Luedtke http://www.danrl.de