If you ever watch any of those "1st Amendment audit" videos on YouTube, be prepared to have taken your blood pressure meds first.
People go in and film stuff and often run afoul of the police.
Watching most of them, you side for the people in uniform, but I've seen a few where someone was taping a private company from a sidewalk.
Annoying as heck, no question, but I couldn't help but wonder about those of us taking videos of trains from the same places. Wouldn't the cops see our types in the same way they see those of this ilk?
I mean we often hear of people having to deal with those with the badges and sidearms while shooting video, but other than when trespassing, wouldn't the police see what we do and what they do as essentially the same?
It makes me realize why so many train fans get rousted by the police for shooting the way many of us do...

To keep it short, you are allowed to film whatever the heck you want as long as it’s on yours or public property or if you have permission to film on a different owners property. Currently I’m dealing with a property dispute which over the years evolved into invasion of privacy with being filmed by neighbors and security cameras aimed right through my kitchen window for no reason other than to watch. When the police were called the only thing they said was they couldn’t do anything because the guy we were dealing with was filming from his own property and since that was the case had the right to do it. So, if your telling me a person can film my private life just because it’s from the comfort of their own home then your damn well going to bet I can film trains on the sidewalk and wave to the engineer just to observe whatever they are doing. In terms of the cops the worst I’ve delt with is just because they thought i was on private property often times I’ve struck up conversation with them and I’ve even had them where they give me other places I can film where I won’t be hassled. Just make sure you look out for the regular excuses like “you know it’s illegal to film in public” I’ve even heard before “do you know what this looks like in a post 9/11 world” said to a bunch of young railfans filming at night even after showing their ID and everything.

It took a while but I finally found someone trying this on RR property. He was quite a jerk about it, but I'd love to see him try this lineside with a camera taking shots of trains: https://youtu.be/0_goyrBcFLA
Many of these "1st Amendment auditors" have very limited understanding of the law and most I've seen online have almost no grasp of what the 1st Amendment actually says, but I must admit I've love to see them take on the RR cops more often.
Some of them really seem to have as their primary hobby to go down somewhere, irritate the heck out of people, get arrested (and always acting shocked when it happens) and then apparently asking their YouTube followers for bail money. If that's how they get their jollies, why not try it out with RR cops more often?
Do you think I'm arguing with you?
I can't count the number of times I've had a cop slide up and tell me I can't shoot from a sidewalk. Heck, I even got told that once by a Conrail cop (I had a few run-ins with them when I was stationed in Maryland in the late 90s, one involved one threatening myself and a pal of mine who was one of the head MPs at Aberdeen Proving Ground, that ended in laughs from us, a written letter from the Provost Marshall to Conrail and later an apology note saying that cop had been fired) that I couldn't shoot from Army property! Seriously, I was standing inside the fence at Edgewood Arsenal shooting stills in 35MM and this Conrail cop walks all the way down from I don't know where, to tell me a crew reported someone shooting photos.
I deeply respect the law, but I told him I was on Federal land and if he had an issue, to go to the main gate and tell them he wanted to come in to cite me for taking photos of trains from inside our fence. he sulked away and I never heard anything about it later.
My point here is that many of us have experienced this and I really hope these "auditor" types start haunting tracksides to show how often it happens to us.