Each installment of “Guarded Opinions” features commentary by museum or gallery guards about the artworks they oversee. This time around, series editor Paul VanDeCarr interviewed two guards, Robert Canedy and Casey Costa, with deep roots in North Adams, Massachusetts, where MASS MoCA, or the Massachusetts Museum of Contemporary Art, is that small town’s big attraction. Canedy offers his take on Sol LeWitt’s wall drawings retrospective, and Costa discusses a piece by Petah Coyne from the artist's 2010 one-person exhibition at the museum.