well brushing technically counts as copying.
iv always held that the final product is what matters.
there are a limited amount of GOOD brushes out there, so as long as you can make them all look individual and unique, iv never had issues.
but that often involves editing or changing shit, merging two together to make something new.
image C&P iv also got no issues, getting shit to map properly, while maintaining some semblance of order in the set, can get quite hectic. cutting a 64x128 random image and then mirroring it wouldnt quite do it for me, but if you go through a process, like, selection, checking what works where, and if the end result is ok, then iv got no issues