Metal Film Resistor: Coating Reliability
You should not depend on the lacquer for insulation. It could become damaged. 
Allowing a lacquered resistor to be in contact with (or even close to) a metal object is not good design. Any potential danger is avoided by preventing contact entirely. 


Occasionally you would see toy-type or other low-end consumer products that had haphazard assembly of lacquered through-hole resistors such that they could rub together and short. Not so much a safety issue (plastic enclosure proper clearances and creepages for safety) or it wouldn't pass safety agency standards, but the safety guys don't care if the thing stops working.