I wouldn't think so, since I believe there is a script in place that makes critical failures damage the goods in the boxes. Besides, even with the +5, some of the tougher chests are beyond the range of everyone besides Raging/Trollformed/Bull Strengthed casters or Barbarian Mountains of Muscle (aka Negnar).
Edit: Soren said crit failures are when you roll 10 or more below the minimum strength needed to open the chest, and I have seen chests in the 30s.