E.g. the repository has /trunk/dirA, without mergeinfo anywhere below /trunk. In a working copy on /trunk do:
svn copy ^/trunk/dirA dirB Now dirB has mergeinfo that is not helping in any way. If you do instead: svn copy dirA dirBdirB gets no mergeinfo. But that is probably related with the note about WC -> WC copies explained by "svn help copy".
-- Stein