Working with as many Indians as I do I would say they don't have the same understanding of boundaries as we do. If you explain to them that it is considered rude to just walk around on their neighbor's property that could be the end of it.
you know what's weird... my toddler runs around into other backyards and we chase him down frequently. i don't walk on other people lawns with regularity but occasionally if i'm trying to get a better look at something i'll go across their lawn. when someone is out mowing we all walk over to say hello, etc. i wonder if some of the difference is there isn't a "shared history" with the new neighbors so there is no trust built up.