Scope mounted spot lights?

[MartinHunter]

I have been thinking about getting one of those scope mounted spot lights for my 20-250 for a long time. I have never seen anybody use one on any night hunting preditor shows and I was wondering if that is because they do not work well? I was also wondering how hard they are to mount, if they effect accurecy, if they come loose with light recoil, and if they are easily detachable? Any help would be appreciated. Thanks
Michael