I don't think this is currently possible with Byobu; we use it on Discuss too for moderative purposes. But this is always initiated from the side of the Moderator, not the Member.
I do think this could be added though, although a contribution like this would need to be approved by @FriendsOfFlarum first and foremost. If they decline, it could be created as a separate add on to Byobu.
Either way, provide some more requirements on how you think this should visually look and work and we could move this discussion toProposals to get it crowdfunded.