Miss Manners: Do I tell my dear friends their perfume gift was a knockoff?

DEAR MISS MANNERS: My signature perfume is a well-known -- and expensive -- classic scent. For my last birthday I received not one, but two generous gifts of this perfume: one from a dear lifetime friend and another from a beloved cousin. Both live a long distance from me; we rarely meet face to face.

The problem is, both were knockoffs. I know this scent well, and the fake bottles were easy to detect. Both generous gift givers bought the perfume online. Both are financially comfortable and would never knowingly purchase knockoff anything.

The perfume is nice, but not the real deal. I use it to refresh closets and clothing drawers.

Do I tell them it’s fake? Their generosity is endearing. I certainly don’t want to embarrass them, but I also don’t want them to be duped. I’m losing sleep