Version: (using KDE 4.3.2) Installed from: Ubuntu Packages I've seen this feature in some Windows driver but think it's good idea. When e.g I have configured main monitor on left and secondary on right I could have one of the windows maximized on left screen, then when I want to close this window It's quite hard to move fast to right upper corner and at the same time not move cursor to right monitor. So I suggest to detect speed of cursor approaching to edge of left screen(in configurable way) and basing on it allow or not to pass to another screen. I don't know if it's good idea to implement it in some KDE component or better in X'es.
The mouse pointer movement is controlled by the X server, so please report this wish to http://bugzilla.freedesktop.org/