So, does that mean that sites would need to fallback to existing practices for these users (or for custom forks)? So, these users get the worse ux and that's considered "supporting custom browsers"? Now sites can spend less time and resources on detection, but wait...what about the 5-10%? So IT departments will be less likely to spend precious dev time and funding on improving detection due the overall risk reduction. I'm not sure that's a net win.