Basically, it's the same problem as with "cold hits" and DNA testing.
For example, if you combine face-recognition, driver's license databases, and feeds from public security cameras, you can (albeit currently with quite a bit of error) track someone's movements around town. All of the individual components are reasonably expected. But people traditionally don't expect the result: the state having a map of everywhere they went today, without having to get a warrant to attach a tracking device or to subpoena mobile-phone records.
Whether this should matter legally seems a bit up in the air. The position that it should is sometimes called the "mosaic theory" of the 4th amendment: http://www.michiganlawreview.org/assets/pdfs/111/3/Kerr.pdf
The purpose of the amendment is not to give criminals a certain minimum chance of avoiding detection by making it hard to collect evidence. That is just an incidental result. So long as such monitoring is not used as a means to stifle legal dissent, I have no objection to it.
My 2c. That said, I'm not a strict constitutionalist. The law should reflect the good of the people now, not just what guys thought a long time ago. If it does more harm than good, the mosaic theory maybe should prevail.
The problem in this case is that allowing this type of surveillance allows the state to use the prosecutor's office as a means of harassment. It allows the state to choose who to prosecute first and then go through the intended defendant's recorded life history in order to find the offense. And since no one is a saint (and no one knows all of the laws), the result is that whether anyone goes to prison or not becomes solely a matter of prosecutorial discretion, since everyone is guilty of something and now they can prove it.
Forgive me for thinking that sounds a little naive. That argument could be used to support the repeal of the entire bill of rights and the separation of powers.
Absolute power corrupts absolutely. The whole idea of a constitution is to place restrictions on government power in order to limit as much as possible the amount of damage that can occur when the government is corrupt or incompetent. There are comparatively huge advantages to a government run by a competent Benevolent Dictator. The problem is that in practice dictators tend to be not so benevolent.
Do they? Suppose we pass a law that says the police don't need any probable cause to record all your phone calls, bug your home and office and come into your house and read or copy all your personal documents, as long as they don't inconvenience you or deprive you of your papers. Pretty sure that would violate the Fourth Amendment, even though the harm there is substantially identical to the harm here. Which is theoretically none, assuming the police only target evildoers and never do anything nefarious with the information, etc.
Likewise the First Amendment protection for anonymous speech. Having to disclose your identity to the government before you can communicate with anyone will only cause harm if the government does something untoward with the information, right? But the First Amendment doesn't allow them to require it, because the government could be doing something wrong. We even go so far as to say that the government can't demand the information because people may fear the government doing something wrong (chilling effects), and be afraid to say certain things as a result, even if the government never actually does anything with the information.
Your example of the first amendment is less compelling. The mere requirement to convey your identity is an imposition.
I believe waiting until it is used to overtly stifle legal dissent to object is foolish.
Then you link that to the person having demonstrated at a couple of, say, animal rights protests, get a few neighbors who say that the guy was "weird" and "acted strangely", and bam - you have what looks like an open and shut case of a radical animal liberation terrorist, but is in fact just a vegan who happened to pick up some gardening supplies at a Home Depot and a Pike's Nursery two days before going to a baseball game.
Because the purpose of getting a driver's license is to prove ability to drive. We gave the DMV our photo and personal information for that purpose only.
Another non-driving related item is motor-voter. They take your information and FWD it to the election officials to get more people involved in elections.
We already know law enforcement is recording these events.
But wait, you might not even have attended the event. You might have been walking to your job, your home, going shopping, meeting a friend.
Tant pis pour toi...
Perhaps my comment sounds over the top. But when the TSA (or, the real three letter acronyms behind it) can't even effectively maintain its no-fly list, particularly with respect to ruling out and removing false positives, or even having a policy and public interface for addressing this... Well, for one, my confidence is not particularly inspired.