Google Being Sued Over Trademark Infringements (again)

It seems that Google is being sued yet again over trademark issues related to adwords, its pay per click search engine marketing service.
This time round it’s American Airlines that is taking them to court.
The full story is over on Eric Goldman’s site.
One of the questions he raises amused me:

I also wonder if American Airlines itself has ever bought third party trademarks as keywords–plenty of keyword plaintiffs have engaged in such duplicity, and I’d be surprised if American Airlines has run a completely clean shop.

Of course the question that I’d be asking is why didn’t American Airlines simply request that the keywords be blocked by Google.
They may not act that quickly when smaller fish submit a request, but I would presume that when a big corporate sends one in that they act a bit faster.