I don't agree with using police force to scare people into not protesting, but the more I've read, the more it seems that the police did have some valid cause and warrants for some of the raids, just maybe not all.
The main target of the raids were members of the "RNC Welcoming Committee", an anarchist / anti-authoritarian group. This group's goal, which they have been advertising for over a year, is not to legally protest the convention, and the Republican party's policies, but rather to try to shut the convention down.
From their website, posted a year ago:
We have one year to prepare for the most extravagant theatre in this war on exploitation. That means one year to study maps, prepare blockades, run our sprints, climb fences, craft disguises, find press credentials, procure bolt-cutters, and most importantly, gather those close to us and devise our own plans. The political parties hope to rally their support with all the bells, whistles, lights and confetti that can be expected from a class that cares more about appearances than human life. But we envision a different outcome. We will be here to ensure that when the CNN cameras pan the Xcel center on the first night of the RNC, not one seat in the entire stadium is filled. Our actions will eclipse the RNC. We are going to shut the convention down.
They have a strategy that they posted online (and yes, the annoying all caps was theirs, not mine):
ON THE FIRST DAY OF THE CONVENTION, PARTICIPANTS WILL EMPLOY A THREE-TIERED DIRECT ACTION STRATEGY TO DISRUPT THE RNC. THE TIERS ARE ORGANIZED IN ORDER OF PRIORITY ACCORDING TO THE NUMBER OF PARTICIPANTS; IF A SMALL NUMBER OF PARTICIPANTS SHOW UP, ONLY THE FIRST TIER WILL BE CARRIED OUT, BUT IF THE NUMBERS ARE ON HAND, ALL THREE TIERS WILL BE IN EFFECT.
TIER ONE: ESTABLISH 15-20 BLOCKADES, UTILIZING A DIVERSITY OF TACTICS, CREATING AN INNER AND OUTER RING AROUND ST. PAUL’S EXCEL CENTER, WHERE THE RNC IS TO TAKE PLACE.
TIER TWO: IMMOBILIZE THE DELEGATES’ TRANSPORTATION INFRASTRUCTURE, INCLUDING THE BUSSES THAT ARE TO CONVEY THEM.
TIER THREE: BLOCK THE FIVE WESTERN BRIDGES CONNECTING THE TWIN CITIES.
This group did not just want to shut the convention down, they wanted to shut the city down!
People who were raided but not arrested complained that the items police had the warrant for and that were seized by the police were the same kind of things that would be found in anyone's home (lighter fluid, paint, etc.)
But, here is a picture of one of the garages:
And if it was ordinary household stuff, with nothing illegal planned, why would there be dozens of homemade caltrops?
Yes, unfortunately I believe that the raids, especially the one on the convergence center, may have targeted some people who are legitimately planning to protest peacefully. And I'm not sure the police handled everything as well as they could have. But I also think that they had plenty of time to gather their information on this one. The RNC-WC didn't attempt to hide their intentions. In the case of this specific group, I believe it was a legitimate raid. They were planning illegal activities and that is why they were raided.
Now I just hope that the repercussions of this aren't worse than the original plans of the RNC-WC.