We all knew going in that this is what we were signing up for.
It's like going to a club with a specific dress code. You go there for the atmosphere and the unique experience. And yeah everyone agreeing to not have a phone in their pocket does change how people in a group interact with each other.
In the first case, a third party came up with the idea, and you are subjecting yourselves to their idea. In the second case, it's your idea, and your friends are subjecting themselves to your idea. Really if you are proposing, there's always a bit of "your idea" there, but the "blame" can be shared with someone else who's not in the group.