I've encountered several caches that would require breaking trespassing laws to reach them. Sometimes the signs aren't really close to the cache, but it's apparent to a thinking person that the area of the cache is within that "No Trespassing" region.
I thought that it was against the guidelines to hide caches in such areas. Perhaps the signs are put up after the cache has been placed. Giving this benefit of the doubt, I always post a note about the sign on the cache's site if I encounter one. Personally, I will not trespass for the sake of finding a cache, and I find it very frustrating and disappointing when I encounter this situation.
What are other opinions? What if you can't find a creative way around the trespassing law? Do other people also get frustrated and annoyed by this? Or do you stealthily disregard the law and consider the no trespassing sign part of what heightens the difficulty?