I'm having a fantasy of a procedure where, when you enter the space, you turn off the internal cameras, then turn them on when you leave. Record all events while no authorized personnel are present, record nothing while they are present.
This would still record all entry/departure of authorized personnel, but that is probably a good idea anyway (and could also be recovered from alarm logs). Video record of these events would just confirm that the person logging in is the person claimed.
One other item (I haven't been following this closely and it may have already been said) - any recorder needs to be hardened and maybe kept or mirrored in a separate location.