Vanity Hair (owned by Tabata Jewell) does it too
Just found out when I rezzed an object from them, in a sandbox, not knowing it was UNboxed, got this lovely message:
" !VA! Come rain or shine shouts: Warning! Copyright by Vanity Hair! Rezzing this Item is unauthorized! Reporting & Selfdestructing! "
If you DON'T want people to REZ your creations, LABEL the item accordingly!! One more shop/person I won't shop from.