As the person who created the Porc-411 recording system, I have a few observations to make and a few details to share, especially as several people here are basing their opinions on misunderstanding or misinformation.
First, as best we can tell, there were no 911 or other emergency calls made as a result of Dave attempting to walk 50 yards north on Elm Street to his destination, the building with the large windows which is visible in some of the scenes in the video.
Second, it was not a Manchester police officer who stopped Dave, but a state trooper. As best we can tell, he was eastbound on Auburn Street, happened to see Dave and turned south onto Elm. Dave's crossdraw holster would not have been easily visible from Elm Street as he walked northbound, but could be seen easily by someone eastbound on Auburn approaching Elm.
During the stop, as best we can tell, the trooper called in Manchester PD. "Four calls," as far as I know, is misleading. There may have been four calls between various LEOs, but it's highly doubtful there were four 911 calls. And even if there were, a state trooper would not normally respond to a 911 call within the city, especially near downtown where local police pass by frequently.
My personal opinion, based on my personal knowledge of the events, the original audio and video recordings, and my interviews with the people present, is that Dave did nothing whatsoever to provoke the incident; the state trooper did by making a legally dubious stop. He is quite correct to say, though, that we are quite prepared to defend our rights, and we have assembled a number of tools to assist with such defense.
One of those tools is Porc-411. It's an automated recording system whereby you call and can leave a message of unlimited duration. The message is recorded to a compressed audio file which is then e-mailed out to a mailing list, most of whom are here in New Hampshire (there are 3 or 4 reporters from out of state who are subscribed).
The videographer, who has been recording Free State Project activities for several months now, mixed this recording with the audio from his camera in order to provide better sound coverage, though as you may have heard, it's hard to get good audio off a cell phone.
I don't think a "national" number similar to this would work, simply because too many of the calls which would come in on it would be for events taking place far away from most of the subscribers. If you live in Florida, hearing immediately about something going on in Utah doesn't do you a whole lot of good, since you can't respond by traveling to the scene.
It works as a statewide number in New Hampshire since the state is fairly small, but for most of the rest of the country, I think a series of numbers, each for a particular region, would be a lot more effective, since people would actually have a chance of being able to make a meaningful response to whatever happens to be going on.