Holy crap, I think you might have something there... I never knew copper was a weakness to inverterbrates so that's some pretty interesting advice to have on hand...
Anyway, I never actually done it before myself, but I know copper is actually used in water pipes. The reasons why is because 1.) It doesn't corrode over time with water... and 2.) this element is very stable and unreactive.
So unless anyone else says nay, I'd say this would be a great idea as you'd be qting your plants for 1-2 weeks and it will help even more with getting rid of nasty infestations!
Here, here! To copper!