I copy stuff all of the time. I rarely purchase a pattern (think I have 2x). Most of the time traditional blocks are used in commercial patterns, that is why we like them!
I do not take pictures of others stuff to copy, just remember what I saw and draw it out on graph paper when I get home, so who knows if it is a copy? I will usually throw in extra stuff like pinwheels, ect to personalize it anyway.