The main problem are the Logos and the Brand Names , some stuff are copyrighted and in E.U. copyright it is +70 years after death ... they are not registered as designs.
Jewlery are copyrighted by default , sculptures , drawn patterns ... and list goes on. ( in USA , Netherlands , Italy , Germany , France , Romania , Spain , ....)
Users are liable of damages from the first sale to last up to maximum ... that can go up to *000.000 ended numbers.
Notable trademark to add :
NINTENDO , MARIO FRANCHISE it is in JAPAN registered. Characters are copyrighted and the designer that made them it is alive ...
Shapeways works on same ground like Youtube , owner report , product it is down , if product it is uploaded again , then the owner will sue for maximum damage and second time will not send any report will just end with a paper at home and reading "subpoena".
And that it is no joke.
People can make fan art but without any agreement from the owner , they only be used for didactic purpose , personal use , not sale to none.