@Ed-and-Hugh0 are absolutely right, @Helen. I work freelance from home, which means I'm around most of the day (and evenings as well). I made it very clear in my Space description and House Rules that the sort of guest my accommodation is ideal for is someone needing a safe, quiet home-away-from-home on a short-term basis (i.e. 2-7 nights only), and who would likely be out of the house during the day. Of course, anything can happen - for instance, a guest could fall ill, have a bad headache, or whatever, and not feel up to going out - but at least they know the scenario when they book.
I give keys to my guests, and they can come and go at will. If they intend to arrive home late at night, I simply ask that they do so quietly..