Gotta be careful with Copper Grease as it alters torque settings, and disc bolts should really all be torqued correctly.
Only if you use way too much, I'm only talking about a thin rubbing around the thread
"Technically" it shouldn't be used at all with brake discs, as they're one part you don't want breaking loose.
I can't find the exact post on here that i sent before, but it explained how dodgy the stuff is to use if used with a torque wrench.
After a bit of a ponder, it does make complete sense that you're lubing a bolt with an anti grip lubricant to avoid future shite, but it makes it more susceptible to over tightening by accident, or by seeing a false reading on a torque wrench.
I learned all this when i shredded my rear caliper bolt doing the 'right thing' at 10 or 12Nm using Copper Grease.
Yet oddly enough, if you use engine oil, not only does it lube nuts and bolts in a similar way, but torque settings can be used in total confidence in comparison.
Because i work with very sensitive equipment on a daily basis, i know "right from wrong" so now nip things up by hand, but certain things on the bike, like discs, or header bolts, for example, should be done properly.