On Valentine’s Day 2013, a mother and her two daughters walked into a Barnes & Noble bookstore and put sticky notes strategically on the cover of the Sports Illustrated Swimsuit Issue featuring Kate Upton in a skimpy bikini. Current trespass law at times emphasizes that a mere physical intrusion suffices. Under that “right to exclude” approach, Barnes & Noble could easily prove that a trespass had occurred. At other times, however, trespass law focuses on the “right to use,” and instead seeks to determine whether any given intrusion interferes with the present beneficial use of the landowner’s premises. Using economic efficiency analysis, this article suggests that the right to exclude approach leads to fewer transaction costs and therefore is the economically efficient - and therefore preferable - legal rule.