Avoiding mechanical shock damage on a PCB
If possible don't mount the board directly to the side walls of the housing. Don't mount the board at 4 corners. Use a minimum number of fasteners to hold the board in place (one center fastener and a few edge slots may suffice).  Board mounting holes could be made large to take a standard slotted rubber grommet, the grommet is pressed into the board, it then mounts onto a pin or held in place with a stepped shoulder fastener that doesn't stress or overly compress the grommet. Any board to housing wiring should have a bit of a service loop (for example leave some extra length to prevent stress during movement). Use stranded wire rather than stiff or solid wire. Keep the board assembly lite, specify low mass components, use ceramic caps instead of tantalum or electrolytic (where feasible). If you coat or encapsulate a board be aware of any heat dissipation requirements.  

If cost is not a major obstacle consider using a flex PCB material.  (Thin polyimide or kapton are nearly indestructible.) Stress due to a deformed housing can be almost entirely eliminated. If designed carefully such a circuit could even eliminate most or all board to housing wiring.