Phil, you have a point about colour.
True mines like the claymoor would be totally ineffective if painted in flower power colours. They are however 'spot' weapons for command or tripwire detonation and easy to plot accurately.
OTOH the Russian butterfly type mine, made of plastic to evade mine detection, self-coloured to avoid detection, and scattered along trails etc and totally unplotted is something else again.
A BL755 with its cluster munitions scattered everywhere will have done its primary job on delivery. A secondary function will be to upset anyone moving into or through the area. It will be obvious where that area is so they would achieve their effect if they were painted flame orange.
What about delayed action munitions? You can drop a bomb with a DA fuse up to 2 days. If it fails at any time them it may still go bang years in the future.