As the security depends on the “minting rate” the network should be very secure from the start. As long as the majority of all shares that are in fact able to mint do so, it is not important that there are shares that have not already been distributed.
Only distributed shares are used for minting and voting. This is no technical limitation, but a decision:
As long as the NuShares are still owned by the “Nu DAB (Distributed Autonomous Bank)”, Nu would be allowed to do as it likes; they could be used for minting and voting and I wouldn’t consider it unfair (because they would still be owned by Nu).
Nu likes not to use them for minting and voting and I like that even better 