Some may express concern that the Free Universal Construction Kit infringes such corporate prerogatives as copyright, design right, trade dress, trademarks or patents of the supported toy systems. We encourage those eager to enforce these rights to please think of the children — and we assert that the home printing of the Free Universal Construction Kit constitutes protected fair use.

Today’s manufacturers have little or no intrinsic motivation to make their products compatible with anyone else’s. Indeed—despite obvious benefits to users everywhere—the implementation of cross-brand interoperability can be nearly impossible, given the tangled restrictions of patents, design rights, and trademarks involved in doing so. So we stepped up. The Free Universal Construction Kit is the VLC of children’s playsets.

As we can see from the example above, interoperability is a question of power and market dominance. Most market leaders regard interoperability as an anti-competitive nuisance, a regulatory check on their ambition, or a concession to the whining of lesser players. Quite simply, interoperability is the request of the disenfranchised. And which end-user, in so many ways, is less enfranchised than a preliterate child?

The simple fact is that no toy company would ever make the Free Universal Construction Kit. Instead, each construction toy wants (and indeed, pretends) to be your only playset. Within this worldview, the other manufacturers’ construction sets are just so many elephants in the room, competing for your attention on the shelves of Toys-R-Us. No longer. The Free Universal Construction Kit presents what no manufacturer could: a remedy providing extensible, post-facto syntactic interoperability for construction toys. Let the fun begin!

Lego justified its stance by citing the "commercial" nature of the Spinal Tap video.  But can Lego really prohibit the use of their products in commercial videos?  If you ask the federal courts, the answer is likely "no." It's a lesson that Mattel has repeatedly had to learn the hard way.

But that hasn't stopped trademark and copyright owners from trying. The court summarily rejected Wham-O's claims against Paramount Pictures for the unflattering use of its Slip 'N Slide toy in the movie "Dickie Roberts: Former Child Star." Caterpillar likewise had its claims against Walt Disney (relating to the portrayal of the brand in the oh-so-popular movie "George of the Jungle 2") shot down. Similar claims by Emerson Electric Co. (makers of the In-Sink-Erator garbage disposal) and the Canadian folk band the Wyrd Sisters also failed to go anywhere.