[Clipart] Copyrighted cliparts

[chovynz]

I've hidden these:
http://www.openclipart.org/index.php?pretty=detail/61573
http://www.openclipart.org/detail/16414
http://www.openclipart.org/index.php?pretty=detail/16872



I need someones elses experience and ideas on this one. While I think 
the clipart itself is fantastic, is there a problem with the words? 
Isn't that a recognised brand or trademark of Nike? What should I do 
about it?
http://www.openclipart.org/detail/7981

Cheers
Chovynz