Those ropes/string can't possibly hold the dish. Who couldn't scrounge up 4 large screws or worst case, smaller ones and washers ?
That apartment building with ~12 dishes is becoming more and more common, sadly.... Well, I'm glad to see people moving away from the cable companies (for so many years, 3 out of 4 people wouldn't even consider "the dish" because "it doesn't work when it rains") but the complex or installation companies need a better system than that. I haven't seen that many myself but have seen 5-6 in plenty of places.