Owen,
Thanks. The touchstone for me is whether a registrant can successfully transfer his registration from one registrar to another. With respect to the registrant's DNS service, I believe this is most often provided free of charge by the registrar as part of the registrar's service. As a consequence, when the registrant moves their registration to another registrar, they will also have to move their DNS service. As things stand, I believe this often means there will be a disruption in resolution. And for a signed zone, this also means a disruption in validation.
If I understand your point, you're saying because this was not raised in the issues report, it's not in scope for this PDP. Putting these points together, the goal for this PDP is to reach consensus on how a registrant can transfer their registration from one registrar to another with the understanding they will likely not be able to sustain uninterrupted service.
Steve