We went through a construction process about 1.5yrs ago - where we had moved out of the house ... such people always wandered around on the property when the construction folks were not there on the property (i.e. off hours)

Once I was on the property - a guy stopped his truck, came onto the property and started rummaging through the stuff on the driveway and picking up pipes !! And I was on the property (second floor) yelling my head off and asking him to back off (really scary experience). I tried to call 911 (ofcourse from a cell phone - it never gets connected immediately) - and I didn't know what to do. Knowing that there are a lot of crazy folks around, I didn't quite want to go on the driveway and confront him. This guy took his own time and found two plumbing pipes in the trash and waved them to me, said 'Gracias' and took off in his truck ..[and no, I was not connected to 911 in the mean time]

Then there was the other set of people - who were just curious as to what was going on, what changes were being made and let themsleves on the property, looked around and went their way. Sometimes these people were sent by our contractor to take a look at his ongoing work, sometimes these were people from the neighborhood who were shopping around for a contractor/architect.

After the incident of the guy coming onto the driveway, we asked our contractor to put up a temp fence, which was 'locked' ( they tied it with a metal tie on one end ) when the construction folks were done with their work. So if someone had to come onto the property ( driveway included ) they had to untie the metal tie and come inside .. this proved as a deterrent, since undoing the metal tie was like opening a 'lock' to some extent and was more like trespassing.

i witnessed a father showing his young son how to squeeze between a locked fence to steal some plywood from a spec house. he was obviously too big to get through so he sent his kid.

they were on bikes, and they did come back for more wood !!

Let me ask a dumb question. If the stuff is in the trash, why do you care if he takes it? Isn't that recycling? You should be recycling the stuff anyway.

Of course, I'm not talking about stealing non-trash.

In response to Trudy:

I do not care about the trash, per se. What I was concerned about was that someone was on private property snooping around. The dumpster was not on the street it was clearly in the driveway. Even if you think its okay to tresspass if you stay on the driveway, she then went in the back yard!

Yes, there appears to be more trespassers in most communities. Perhaps it is ignorance of observance of personal property boundries or just a lot of nosey people who feel that they can just wander in.
Unfortunately, the police will only intervene if the owner of the property is present and you have a good description of the person/s.
They can only be held responsible if the owner places a formal complaint otherwise it is good that you are a helpful and watchful neighbor.

Another example of this happened to us this part weekend. Our elderly neighbours have moved out of the home they have lived in for over 50 years and this past weekend we had a huge estate sale next door. I couldn't believe the way people behaved. At present we are having some remodeling done and buyers at the sale decided that our construction was a sideshow to the event. We are still living in our house while the work is being done and it was incredible how these people took liberties. Our driveway was not only blocked, but as soon as I pulled out to take my son to his soccer game, on my return someone had parked on my driveway, there was no street parking anywhere so I had to park on what should have been my front lawn except for the fact that it was the entrance to the construction site. Similar liberties were taken all weekend blocking me in or making it extremely difficult for us to use our driveways. People walked right up to the perimeter of the work and stared at the construction even though they could see me chatting on the phone at the window of our kitchen. They lined up to use our porterpotty and allowed their children to run all over the dirt at the front of the house.

I can't believe that people going to the sale had such bad manners to the neighbours. The estate sale had nothing whatsoever to do with us, but we were considerably inconvenienced by those who had nothing better to do than visit sales to find "hidden treasures". I feel sure that most of these people would not have treated their own neighbours like this, so why did they treat us this way? Is it because they were out of their own neighbourhood, or was it because our construction made us look like a free for all?