PBIS isn't the red light or the cards, per se, ... PBIS is a collection of supports within the school and looks radically different in each school. But there is often some kind of behavioral element, either as a transitional part or permanent, even if that's kinda not the point...
PBIS can be tricky to implement and can have varied results depending on the school population and the school staff. It *can* work well if everyone is on board and the school devotes resources to creating a system that works for them.
To the OP, it's a rare day indeed you find teachers who practice the work of Kohn, especially in public schools where we are given quite extreme behaviors to deal with, often. How I parent my child and how I would teach my own private school (or really, any public school that could actually have a real discipline policy where violence and extreme behaviors were not allowed to continue and disrupt all the other student's learning... meaning, at the end of the day, students could be expelled just like they can at private or charter schools)... is not the same as how I teach all of the time, because I have been put into impossible situations (30 kids per room, 10 kids with extreme behavioral needs, miles and miles of curriculum to cover before we sleep...) where there just simply isn't the reality of being able to allow students 100% decision making and they just aren't going to be intrinsically motivated to study whatever it is we're required to study that day.
That said, we're a PBIS school and the vast majority of our discipline is positive, but as any Kohn follower will tell you, behaviorism is still behaviorism and dangling a reward or token economy in front of a kid isn't so different from the lights/cards... that said, it's still an improvement in my book when you have few supports at your disposal.
Oh wow that run on sentence makes me tired just looking at it, but after teaching and parenting all day I'm kinda too spent to even re-read it... so I hope I make some scrap of sense.