I have already answered this exact question several times, but since you felt the need to ask again, I'll cut and paste my response for you again.

The comment that I initially replied to was saying that boobytraps in general should be legal on private property, so that is what I am responding to in my reply. As for why the sign should absolutely not be bootstrapped, these signs are put out by the road. You know, where burried water and electric lines are, that a utilities worker might be servicing. So a utilities worker may need to move the sign to do their job, which was the first example I gave of someone having legitimate reasons to be on his property

Before replying to this, try reading one of the dozen other comments I have left in this comment tree before you repeat the same questions again.