[kijinbear]

I think it depends on what you mean by "due process." If you mean "whatever the law says the government can do, and/or what the government customarily does," there may have been no violation of due process.

However, the phrase "due process" also often means "what the law should say the government should do." Such an interpretation usually appeals to a higher moral authority, the Constitution, etc. This is how people often criticize the PATRIOT Act for violating due process, even though the PATRIOT Act defines clear processes to be followed. These people are saying, in effect, that the processes defined by existing law don't count as "due process."

You are right that court challenges are the way to fix problematic laws. But I disagree that "none of these people have been deprived of due process," because I think that any process worthy of being called "due process" should involve, among others, presumption of innocence until proven guilty, and a bunch of documents signed by judges. I don't know what the law is really like in the US, but seizing property in the absence of a criminal conviction (except temporarily, to gather evidence) sounds like a gross violation of due process.