Interesting discussion. As a newspaperman for onwards of 40 years, retired from one newspaper where I was there for 25 years as a staffer, Department chief and Department editor I've had a lot of experience with stringers.
All full and part-time staffers got State Police press IDs, City Press IDs, NFL plastic permanent sideline passes, various University permanent sideline passes amongst various other IDs including New Jersey Turnpike press IDs. I have to admit I also accommodated some trusted stringers with some of these IDs as permanent and some as daily issue.
Pennsylvania PP tags or press photographer tags which are front and back do allow while performing newsgathering duties and with a yellow flashing light to ignore certain traffic restrictions such as turning around at authorized vehicle only Highway turnarounds amongst other benefits. State Police also issue visor press parking permits.
You're always going to have your Arthur Selig wannabes who I would have to swat away as gnats... of course until that day they were the only ones with the shots I needed for the front page. I never trusted them and never gave them assignments. Other stringers and interns performed better than some of my deadwood staffers but they were far and few between.
A good rule of thumb at an emergency scene or crime scene is park down the street so you don't get caught by any active fire hoses or equipment blocking you in, hide in the shadows with a long lens and get everything you need for the front page and the inside. Always keep your press ID in your pocket. After you have everything you need then show up at the scene to try to get information from cooperative Public Service people. Some cops were cooperative and some violated First Amendment rights at the drop of a hat. You wash my back I wash yours.
I remember I was sitting on a murder suspect house waiting for something to happen or to get any license plates I could. Later a homicide detective called me and said how did you know and what do you know? I gave him everything I had because I knew I would get paid back. If he had treated me badly in the past I would tell him to buy tomorrow's paper and hang up on him. Same with the mayor.
Stringer's Crossing police lines or acting unprofessionally always hurts the professionals.
Of course I'm from yesteryear and the whole business has changed. We had to confirm every story three different ways before we could publish it as news and not opinion or editorial content. That's all changed now. Manipulated pictures, set up photos and Publishing rumor for politically-motivated reasons as above the fold headlines is commonplace now.
Stringer's will always be part of the process and keeping them in line will always be challenging.