in a different field (graphic design) the problem are -quite -the same, maybe more difficult..
i.e.: i design trademarks and logos, plus websites, it's my job since 15 years ago.
now i have a style , after ALL that years..customers came to me ,even if i'm way more expensive than others here.
in my style you -if you like visual communications- could find influences of futurism, of russian constructivism or swiss school..
but you will not find a sign directly took from ,say, a print of depero or a poster of rodchenko.this said, an old customer of mine, show me a portfolio with logos slightly different from mine, prepared from a new designer..
i cant do nothing about it. they arent the same, but they have big pieces of my work inside...for the law here, if you have full of lawyers and a lot of time , you can start a sue..
i know this person, he "growed" and worked under my "influence" , he always said that he loved my style, but now that period is .."forgotten".
sorry for long and maybe confused post..the moral is :
as long you use the influences and works of others for producing somethin new -and also if you say that you are using other's work- for me it's fine.
if you use my work and efforts and style, and you say it's yours, you are a thief. but ther's quite nothing i can do.
positive tought: most of times a motivate customer ,before or after, will recognize the model from imitation...i hope.
my best ,and sorry if i'm OT