said by nunya :

You could spray them with a hose (They even have motion detector sprinklers for "deer").
Also, put on a stained "wife beater" shirt. Set up a lawn chair and drink heavily. Smoke a few pack of cigs while you're out there too. Then, when people walk by shake your fist at them and call them "whipper-snappers".
That oughtta do it.

Seriously though, I'd start with a "No Trespassing" or "Keep Off Lawn" sign. The deer sprinkler would be *extremely* entertaining - you must admit.

said by rgoltsch :

A few well placed, and highly visible, dog turds should do the trick. Make them think they are going to risk walking in a minefield and they might choose another path. No one likes to be cleaning poop off their shoes.

We have a weimariner, so we have plenty to spare if you need to come pick some up.

Ron

said by Babaganooosh :

Just let them take the shortcut. Easiest solution I think. It's not the end of the world.

Whatever happened to friendly neighbors?

said by WALL_E :

The people cutting across his lawn are trespassers. If they were invitees, the OP would be liable and have to reasonably provide for their safety.

However, because they are trespassers, the OP is only liable for any injury that results to trespassers as a result of an intentional act on his part. For example, if he ran fishing wire across and someone tripped and hurt themselves, he would be liable.

If a trespasser cuts across his lawn and trips on, for example, a rake the OP leaves in the yard, he is not liable b/c the injury was not the result of deliberate action on his part.

said by Daarken :

liability...
that is what it will come down to.
build the fence and your liability is reduced, do nothing and your chances and liability go thru the roof..
good luck