The argument about "violence" and then saying "protest doesn't qualify" isn't true. Because it doesn't say you have to commit an act of violence, it just says you have to pose a risk of committed an act of violance at some point in the distant future. So if you protest and they say "hey that guy is really adamant in his views, he might resort to violence if he doesn't get his way" they can use that as justification for seizing eveyrthign he has.
I think folks here are forgetting about something really important. Rights aren't about what law enforcement DOES, they are about what law enforcement CAN LEGALLY DO. So for example, let's say they made it legal to search houses of terrorists without any kind of warrant. You can say, "well they are only going to use it on terrorists", but the problem with that is no due process was given in order to determine the person is in fact a terrorist. As a result, law enforcement can make that decision without oversight. When they can do that, even though they probably WON'T searhc yoru house, they CAN. Because they CAN the 5th ammendment is no longer valid.
You can try and say "oh they won't abuse it, you're being paranoid", and my argument is simply, just because they won't doesn't matter. The point of rights is to remove the possibility of abuse. The bill of rights protect the American people from the American government. Giving the government the power of search and seizure over US citizens without a warrant, UNDER ANY CIRCUMSTANCES, compeltely invalidates the 5th ammendment protetions against illegal search and seizure. Will they search your house? Probably not. Can they? Most definitely. THAT is the point.
EDIT: Correction, 4th ammendment deals with search and seizure. 5th ammendment however address seizure of property.