Originally Posted by DarkFlights
Might it be worth looking up photography copyright laws in your country?
Here in the UK, if someone is outside in a public setting, they have no right to NOT have their photo taken, and they do not own the copyright to their image. As someone who attends a lot of themed events in the course of my own work (not photography, but I talk to a lot of both amateur and professional photographers), I often hear people grumbling about "togs". But, fact of the matter here in the UK is that if you're in a truly public place (not a pub or a shop, but on the street outside, for instance), then you have no expectation of privacy under law and can neither stop photos being taken of you, nor claim copyright of them or your image.
It's possible you may have similar laws in the USA?
Other countrys other laws. If you would do this in Germany you would be in deep trouble.
We have very few exceptions where you would not need the permission of the person(s) even if you take a picture of a of a group.
As an example if you would take a picture of of a landscape and that would be your focus and you can see some people that would just crossing over a street, that would be ok if the are accessory parts of it. If the group would be the focus of your picture then not.
However if you would take a picture of said group at some event like the G20 in Hamburg then it would be ok, again except your focus entirely on this group and not on the event.
There is another point that would be different, like if you would take a picture from our chancellor because persons of contemporary history (historic persons) has another exception rule to it.
It's a bit complicated and our law loves it.
In German there is a webpage that offers more insight: https://www.rechtambild.de/
about the issues here.
So publishing pictures without a proper model release can get your fast into trouble, adhortatory letters are quite common and even the first one cost money......