As for marking queens, no one has mentioned my favorite reason for marking
queens-- it pretty well tells me that the old marked queen is no longer in
the hive from swarm, supersedure or what ever.
I would mark any new queen just to verify the preceding happenings,
especially in less visited apiaries where swarms may be missed.
Could the disappearance of missing marks be due to another queen being
present?

 While I'm on line, it would be really helpful if posts would include the
State/Province/area and country so some of us newcomers could relate to the
conditions the writer is discussing.  As for me, I find that in real estate
location, location, location is important.

Dan Veilleux & Janet Montgomery
Vilas, NC
Blue Ridge Mountains