Metallic screws, nuts and fasteners seem like a common way of attaching PCBs to enclosures. Are they, especially stainless steel, also a CDM or direct metal to metal discharge risk?
For instance, stainless steel fasteners may not stay connected to a magnetic tipped driver, and could be more likely to fall onto a PCB during assembly. I have memories of bags of coins and screws being shaken causing ElectroStatic Discharges caught on an antenna during a symposium. A stainless steel screw, standoff or nut dropped on a PCB seems likely to generate similar damaging discharges. Additionally, it doesn’t seem like well grounded tools, personnel, or dissipative worksurfaces would have much of a mitigation affect.
Would zinc plated or galvanized fasteners or some kind of plastic fastener be preferred, as the fasteners could be less likely to be dropped on a PCB or create direct contact discharges, or are dropped fasteners on a PCB not likely to cause ESD damage on a production line assembling PCBs in an enclosure?