Keep in mind that most host families want what's best for both sides. Their intentions are usually to protect themselves and you. To me communication is the alpha and omega (very important). If something is not clear, ask. Be honest and open. Talk with your host family. Inform them about your concerns. By letting them in you earn their trust, and they get the chance to earn yours. Whenever I've been unsure about anything I've talked with both my host parents and the same way around. They have listened, explained, been willing to discuss and showed understanding. I think this is one of the main reasons why my year has been so successful. I hope future exchange students will experience this type of relationship with their host families as well. It makes the challenges decrease and the sense of comfort and safety increase.
I cannot talk for everyone, because I'm just one in a million. Neither do I have the right answers. Every scenario have different outcomes. Life is unpredicatable.
However, it's a good attitude to start your year abroad with.