Here's a video from CMU TV of the sound cannon in action:

http://www.youtube.com/watch?v=TNcKexj2cYU

I assume the reasoning goes: if you want to stand around, you need to have a permit to do so... and you are free to apply for a permit, so there's your freedom to peaceably assemble.

Here's what the Pittsburgh Police have to say about it:

http://www.city.pittsburgh.pa.us/police/html/spec_event_perm...

From Regulations (http://www.city.pittsburgh.pa.us/police/assets/special_event...)

II.k. First Amendment Activity. “First Amendment Activity” includes all expressive and associative activity that is protected by the United States and Pennsylvania Constitutions, including speech, press, assembly, and/or the right to petition. For purposes of Chapter 471 and these Regulations, commercial advertising that is regulated by the Zoning Ordinance or elsewhere in the City Code is excluded from this definition.

II.p. Public Assembly. “Public Assembly” means a group activity including but not limited to a demonstration, march, meeting, parade, protest, rally, or vigil which involves the expression of opinions or grievances of persons for a common purpose as a result of prior planning and which interferes or has a tendency to interfere with the normal flow or regulation of pedestrian or vehicular traffic upon the streets, parks, sidewalks, or other public grounds within the City or does not comply with normal and usual traffic, regulations or controls; or which occupies any public area open to the general public to the exclusion of others.

So it seems like the kids standing around in the video would not have been breaking the law if:

1) they were organized
2) someone applied 14 days in advance
3) they paid $125 for the application

But wait! On page 22, Exhibit A-3 provides examples:

"First amendment activity that does not constitute a Special Event (e.g. does not block a sidewalk or close down a street). Example: Sidewalk protest in front of the County Courthouse; Leafleting or gathering petition signatures on Grant Street. Permit Required? No. Fee Required? No."

So, perhaps if those kids were standing on the grass instead of the sidewalk? In that case, they wouldn't even need a permit. i.e. they wouldn't need permission... i.e. they would be _free_ to assemble...

...and in fact, they would be free to assemble even if they were on a sidewalk, according to Exhibit A-3.

So I'm confused here. In the video I linked, did they require permission to stand around like that? Were they breaking any laws at all? Would it have somehow been _more_ legal if they were organized, and had applied for a permit?

Essentially, the question is: how could they have continued to stand around without the police shooting them with the sound cannon?

EDIT: ...and another question: is it really freedom if you need permission? For example, you never need to ask permission to say something, irrespective of there potentially being consequences for certain kinds of speech (e.g. slander, which might land you in court).

If your freedom to assemble is contingent upon anything (e.g. permission, which isn't guaranteed) then it's not really "free as in libre," is it? ...and if your freedom to assemble is contingent upon an application fee, then it's not "free as in gratis" either. So is it free at all?