If the OS intercepts keystrokes, the UA won't see those inputs. But that's the same for everyone. But may be an accessibility if you can do it through mouse but not keyboard. Based on the second sentence it's a P1 item. In the absence of notification, serious accessibility problems.
People think that their history mechanism is broken.
People often work around by shutting down the browser window. If pseudo-elements supported. There are a lot of superfluous links on pages, notably portal pages. I think it's a P2. I think P1, but can live with P2.