regarding some of the posters saying that it should be arranged that the Non-frum guests should be attending a Shabbos meal at a nearby Shomer Shabbos home so they can walk there…..
First, YOU are the person they know and have a Kesher with….They want to spend time with YOU not a stranger (to them) who happens to live in their neighborhood.
Second, I would say that most of our Shabbos guests do not live walking distance to anything Frum. Remember, us..as a Frum Kehillah always try to reside in a Frum neighborhood, near Shuls, Kosher Markets etc. Someone not Frum is looking for Cheaper housing and living closer to restaurants, movie theaters and malls (and bars).