No, not any terrorist attacs etc..
It's the way our western democracys soon will take away the foundation of democracy in their fervour to crush every terrorist their is.
The danger with this is, if this goes through, is the way the goverments (and their various versions of a Secret Police) seems to get the right to decided who's a terrorist or not, based on information gathered with questionable methods, and doesn't even need to provide real evidennce in many cases. They get the rights to monitor every single citizen's phone, computer, mail etc, activities.
Until now, they basically had to show a probable cause for investigation. They haven't been able to use all kinds of databases, at least not several together, unless a court deems it worthy (in the interest of protecting the privacy etc).
Soon, they could basically freeze your bank account and possess everything you own (At least computer, books, CD-Rs, notes etc) without putting forward hard evidence as long as they say an ivestigation is going on. Etc, etc.
Basically, say that you've shown interest in Greenpeace and is on their mailing list, or has donated to them sometime (maybe 10 - 15 years ago), and their deemed terrorists/or criminals, they can freeze your money, take away your computer etc, because of that. They only need to say an investigation of Greenpeace is going on. An investigation they can basically do on a whim.
USA is on their way to make a law like that, UK is very close behind. EU has suggested similar laws. There has already been protests about it in Germany and Norway, where civil rights people has seen the laws being broken recently.
When USA made up it's mind about Osama Bin Laden, they decided to freeze all his money, and DEMANDED other countries did the same, or those countries would suffer (as in.. if you don't do as we say you can kiss every single USA business goodbye) which made a lot of countries having to change their constitutional rights).
Hmm.. why is I'm thinking German laws in the 30's/40's, which was used against the jews, the Soviet Union and China, when I hear the latest things they want to do.
Many says: Hey.. I haven't done anything, and it's good they do this to get rid of the scum of this Earth, etc etc.. But, if this goes through, you're very close to being ruled by dictators. The only way to be entirely sure you're on the right side of the law, is to give money to organisations such as Greenpeace or Amnesty International etc. To be sure, you better agree with the ruling goverment etc.