Maybe the posted signs should read -

"If you want to hunt, have the decency to ask."
......"Hunting by Written Permission Only".......

Something I've encountered around here, more than once, is a piece of property where you do have full permission to hunt is suddenly posted and nobody knows who put up the signs. Just this fall, one 160 acre tract that I have standing permission to hunt suddenly had a posted sign on the gate. The owner was as bewildered as I was.

In Missouri, purple paint on trees or fenceposts means POSTED, NO TRESPASSING. Heckuva a lot harder to tear up.