It's a lot more complicated than that. By choosing the name blackjack, Samsung is, arguably, taking advantage of a name and goodwill associated with the Blackberry name. -Things that, unlike RIM, Samsung has not spent years cultivating and paying for. Moreover, the device itself, and the services associated with it, may not have the same features, quality and support as a Blackberry -nor will RIM have any control over what happens with the blackjack. If the blackjack turns out to be inferior in any way, is supported inadequately, etc., that negativity will flow back to the Blackberry name and harm RIM. -all because of the confusion in the consumer's mind between the two. It isn't so much an issue of the fairness to Samsung or others in keeping people from using a name of their chosing, its a question of the fairness of subjecting RIM to harm (actual and potential) while another party takes advantage of the Blackberry name.
RIM is unlikely to be able to stop any random product from being called a black___. You want to name your new hammer "the blacksmith," RIM isn't going to give it a second thought and the law is unlikely to give them the ability to stop you. When it's a product in a similar market niche though, it's another matter entirely.
I guess I see it the other way. In my view, it would be ridiculous if RIM couldn't do something about it.