I think this behavior is not helpful:
“Any replicants of the document you are moving [using the Classify window] are deleted. The document is only placed in the new locations which allows you to precisely classify the document again without having to manually clean up the old replicants.”
It penalizes me for seeing new connexions. Or, means that I should use tags or duplicates instead of replicants. And that I think is what I will do, to avoid having a perceived relationship between items removed automatically.