Because if you have to have a mando for safety, that means you've intentionally designed a hole where there are safety concerns.
Well, yeah. But given an existing hole with safety concerns, isn't adding the Mando to deter the dangerous route a good idea?
Specifically I am thinking of Dretzka, and the couple holes there with mandos that prevent the giant hyzer out over the road. I don't see how those could be seen as a bad thing. They prevent a ton of shots from going into the road.