There are machines that are "self-aware" in the sense that they run a simulation parallel to the NC control, slightly advanded in time, to catch catastrophic crashes and ESTOP the machine. Cutting into the machine bed can be _very_ expensive.
How aware? Do they have any vision? Can they "see" or otherwise "know" about the cutters / workholding?
AFAIK the crash guard is a separate component that relies on 3d models of the machine and the tools, it doesn't see anything.
If you workholding is weak and a piece comes loose the crash guard probably won't make a difference.