Whether the owner has completed 2FA activation. Independent of presence: an inactive robo is not usable even if signers are online, so callers gating on usability must check this too (see Salt.getRoboQuorum).
Whether at least one of signers is online.
How many of signers are currently online.
The relevant robo signers and whether each is online.
The live presence of a set of robo signers — an organisation's whole roster, or the robos enrolled on a single account.