ooooya,
The knurled screws are the way to go. Take a Sharpie and mark one of the "knurls". Then you have a reference point in case someone messes with them. Of course, if they take them all the way out, you can use the Sharpie to write "Help!" somewhere visible. Then, if you find out who did it, you can use the Sharpie in many creative ways....
Hmmmmm, I guess a Sharpie may be more important than the knurled screws.... oh well, your results may vary...
