The mailing list for listmasters using Sympa

[address@concealed]

My user base has an entertaining habit of "shotgunning" messages to many
different groups which tend to have similar (but not identical) memberships. 
If
one message is sent to several sympa lists on the same server, will the
daemon(s) cull the duplicate member addresses so that a member who is part of
all the lists receives only a single message?

This is not a deal breaker by any means. It's an annoying habit, won't mind a
bit if they have to learn to actually pay attention to what messages go where.