10 25 2005: Thank you for your input - I should provide more detail. Criminals generally are lazy and spend as little time at the scene as possible. I could imagine special high traffic/great display location circumstances where the criminal would take the time, but I suspect it would be rare that an "artist," and I use the word loosely, would bring enough coating and application equipment with him/her to paint over the patterns and then wait for the paint to dry so that the graffiti could be properly applied. It's - much - easier to move to an easily accessible untouched canvas down the block. And, unfortunately, many of the techniques in crime fighting involve simply persuading the criminal to move past your valuables and on to easier prey.

Suggestion: Produce fencing material that is not mono-color. The design could include flowers, galaxy stars, or other repeating motifs that would provide an attractive but otherwise poor background for graffiti. Pattern creating paint rollers could "roll on" "rubber stamp like" motifs on otherwise mono-colored walls.