Well the point of it is that it's there to get oiled and greased up just like denims, if it gets excessively soiled it gets exchanged. What next are we gonna have cellophane left on the denims incase they get soiled too.
They have to wear this PCS to the mess/psf/wherever so it can't get minging like a set of denims. It isn't dirty clothing like denims, it's to be worn everywhere.