Andromalia
Pardon my french
How would you feel if you wrote some riffs with your band, and a few months later, one of your bandmates leaves, joins another band and uses those same riffs in their songs? You'd be pretty upset.
If I were getting James Hetfield's paychecks I would certainly not.
I think the ethical line is when you stop wanting to own a guitar and start thinking about earning or saving money. If i want a RG 1527 clone with an ebony fingerboard and Ibanez doesn't make it, I'd have no qualms copying it for myself since Ibanez won't sell anything like it to me.