I'm siding with the facebook poster on this one. For a number of reasons..
1. Don't call me a dickhead/asshate/douchebag when I ask you to respect my home and property.
2. If it becomes the standard to have people walking through your yard, no one will care. And by that I mean that when your neighbors see people walking through your yard and around your house, it doesn't raise their eyebrow as something being wrong. And then, weeks later when that strange guy is making about 8 trips back and forth across your yard, casing the joint for the best way inside, no one is going to give a shit because it is expected and allowed to have random people walking around your place.
3. We have the same problem in my neighborhood. Kids wandering around through people's yards at night and "walking home". Well, last December at 9pm my two daughters came running down the stairs crying and screaming that there were people in our front yard doing stuff. These 4 boys "walking home" were going through people's front yards and knocking down christmas decorations and tossing rocks. 4 boys, 12-13 years old.
And now, I'm looked at as "the bad guy" because I had the sac to go out there and round these four little fucksticks up and walk them around the neighborhood putting people's yards back in order that they fucked up. Good judgement won out and I didn't go with the original plan of locking them in my garage until their parents came over to clean up their messes and claim them.
Does it suck? yes. Do you have to be vigilant? yes. If you give people a single fucking inch and leniancy, they will take that as a green light that anything they can do, they will, and not face repurcussions. You need to nip that shit in the bud and enforce the standard. When people call you an asshole for holding the standard, don't feel bad and cave in. You stand your fucking ground and hold steady and don't crumble and let people walk all over you (or in this case, walk all over your yard).