I had been hosting for a number of years - usually I check the person's background. There was a person who had recently pled to reduced charges after a fraternity hazing that was nothing less than sexual assault.
Having a wife and two teenaged daugthers at home, this is why I do ask for 48 hrs. notice. In the first instance, I had two Argentine guys. There would have been no effective background check that I could have performed. In the second, it was two Americans, which I could have effectively checked if I would have had more time. We also hosted a woman I met through CGOAB. She was very concerned about this issue too, since she was cycling cross-country solo.
I think we have to feel like we are able to set our own boundaries, and to have those boundaries respected. If your boundaries do not fit with WS, then you made the right choice for you.
For myself, when acting as a WS guest, I do plan out my routes pretty carefully and pretty far in advance. I have varied a bit, but I've also never had an expectation that I would go from WS host to WS host. I built a few days in between my two WS hosts on my last trip, and that seemed to work pretty well. We actually ended up shortening the route a bit in-between to accomodate my daughter's limitations, but we could have just as easily exapanded it by adding side trips. Maybe when I get around to doing a solo trip that is longer than 10 days I will feel like this is not practical, but for now, planning is a necessity and it works well for me.