[slf4j-user] Use of Markers : life changing events

[Fred]

I have seen discussions of the proper use of markers in two other threads.
http://thread.gmane.org/gmane.comp.java.slf4j.user/236/focus=238
http://thread.gmane.org/gmane.comp.java.slf4j.user/786/focus=787

My question is related to 238 (I believe).
A logger is identified solely by its name.
When two logger instances are obtained with the same name it is the same logger.
Can the same be said for markers?
If there are two markers (M1 & M2) with the same name in separate threads
and M2 has a marker (M3) added to it (M2.add(M3))
does M1 also have a reference to M3?
Does the addition of M3 happen at a particular time or is it retroactive?
The same questions but for 'remove' rather than 'add'.