yes but... the reality is that the Arduino foundation could never afford what it costs to oversee world wide trademark compliance. In addition to that, they would have to immediately start sending "Cease and desist" letters to those who have used the trademark on their products, as trademarks have to be defended consistently in order to be valid. Those cost $500 a pop, and you would just pray that the person desists, because if they don't, it'll cost you thousand more. Any smart infringer's lawyer will just bog things down, so that the trademark enforcer can no longer afford to pay the mounting legal costs of enforcement. This is the sad but true fact of it. If your trademark lawyer spends four hours on defending your trademark one week, the bill will be in excess of $1000. If it takes forty hours... well then you're screwed. and if it goes to court, you're really, really screwed.
Take it form Linus Torvalds himself, who said the following while explaining the licensing fees charged by the Linux Mark Institute:
"Linux founder Linus Torvalds is defending protection of the Linux trademark and insists that sublicensing is a loss-making operation.
Last month, a lawyer acting on behalf of Torvalds, wrote to 90 companies in Australia and asked them to relinquish any legal claim to the name Linux and to purchase a license from the Linux Mark Institute, a nonprofit organization that is the licensee for the Linux trademark.
... Companies will need to pay between $200 and $5,000 to sublicense the Linux trademark, which led some in the open-source community to accuse Torvalds of cashing in on the success of Linux...
"Not only do I not get a cent of the trademark money, but even (the Linux Mark Institute, which actually administers the trademark) has so far historically always lost money on it," Torvalds said in a posting to the Linux Kernel Mailing List. "
If it's not cost-effective for Linux to administer their trademark, it sure isn't going to be for Arduino. It is a sad fact of international copyright law that trademark and copyright enforcement is for people with money. You do not ofter (ever?) see cases of ordinary people going to court over their trademarks or copyright: it is always a corporation, a publisher or someone with money to burn.
Seen in this light the Arduino trademark is unenforceable. I can't imagine that you have 20K sitting around per year for enforcing it. I also can't imagine that you'd want to spend any time doing that! It's counter to what the project is about. So why not just let it be free
Daniel