I've seen some doors in Europe with mixed barrel hinge (Fr. "paumelle de Paris") orientation. Unusually these have the pivot pointing up, but occasionally I've seen a door with one of hinges mounted the other way around, i.e. with the pivot pointing down. Is there a reason for this?
For outdoor use I understand this is a bad idea because a barrel hinge will gather water when mounted upside down. The ones I saw upside down were all inside doors. Also, it wasn't done because of the lack of proper parts (left vs right hinge). They simply rotated the hinge completely with the pivot installed on the door rather than the jamb. I don't get it why anyone would do this.