Disagree. You want them rigidly held in place as *any* flex in their mounting will add up to fatigue failures over enough time. Realistically, that means glue

Disagree. You want them rigidly held in place as *any* flex in their mounting will add up to fatigue failures over enough time. Realistically, that means glue or a screw-down anchor that exerts tension--and if you have such an anchor you need to beef up the substrate also to avoid it deforming the case over time. Glue is thinner and lighter, thus it wins in the market. Likewise, cases are glued because providing waterproofing via glue is thinner and more reliable than providing it by gaskets and screw-down anchors. Simple observation: I have a chest strap heart rate monitor, uses a coin battery and is rated for swimming. What's the biggest failure mode? Imperfect seal of the gasket against the stuff around it permitting water intrusion. (There is a redesign that is supposed to be more reliable but since mine never gets submerged it's still working despite once I found the gasket was clearly not properly seated.)