Dave, I hate to have to apologize for IDIOTS, but that's what we sometimes have to do (apologize, that is).
Where exactly do you live? Is there a marked trail nearby? How far into your yard are people riding? There’s a easement of about 15 feet along the edge of the road. It is legal in most areas to ride on the non-road side of the snow pile, within that easement space. I have seen some people erect fences or put up tape to block the way. It is actually illegal to do that, and a homeowner can get a visit from the police for doing so.
However, that does NOT make it okay to tear up your lawn. I’d be ticked too, and I’m a snowmobile rider. The best thing to do is to work with the local club. Give the Webster Ridge Runners a call
http://www.websterridgerunners.com/main.shtml. Sleds in NY have to be registered! You can get the numbers off the offending sleds, and call the police.
I live in Farmington, but I grew up in Webster. I enjoy riding the Webster trails, when there is snow on them. MOST riders are respectful and considerate individuals. I doubt any club members rode through your yard, since the trails only opened the 26th, and there was no snow on the ground then.
I’m sorry that a few have to make the rest of us look bad in your eyes.
As for riding through private property: Pretty much ALL of the Webster trail system is on private property. There would be NO trails, if it were not for generous landowners who are gracious enough to allow riders on their land. The 40 miles of Webster trails run through the property of some 80+ private landowners.