As with any advertising campaign, Google AdWords does have some limitations as to how you can target for searches. This is done thru the illegal keywords set. What are illegal keywords? In general, you are discouraged from using keywords that are trademarked by entities other than yourself. Google has precluded itself from being involved in disputes involving trademarks, and has therefore explicitly outlined in its policy that you should avoid this,too.

Google has apparently already been involved in legal battles over trademark issues in the selection of AdWords keywords. Hence, while the Google trademark policy does not really prohibit you from including trademarked keywords, they will not be held liable for any disputes nor any other legal issues arising from the use of such.