How to Assign a Role to a Visiting Toastmaster?

Sometimes, a Toastmaster who belongs to another club visits one of our meetings, often to give a speech.  But when editing the meeting agenda, the only assignment options are registered members of our club.  Is there no provision to manually enter the name of a role assignee?

Create a member called "Guest" with no email address, and assign the role to that guest.

Thank you, Brian. I thought of that, actually, and created a fictitious member called "Visitor". The system fabricated a false email address and entered the new pseudo-member struck-through pending opt-in--which of course will never happen. I also tried giving "Visitor" my own email address--which the system would not accept due to that address being already in use.

Have your admin check their email inbox.

What my two clubs do is have non-member entries, in braces, in the FTH Members table.  This method allows a non-member to be assigned to a club meeting role, but does NOT allow him access to the agenda, which, in my opinion, he should not properly have.
Example: Joe Blow is a guest who is filling the Ah-Counter role.  We use the {Guest} Members table entry to assign the role to {Guest}, then put a note in the Meeting Notes box on the agenda that Joe Blow, a guest, is serving this evening as Ah-Counter.
Attached is screen shot of how we do the Members table stuff.