What kind of safety are you referring to? Are you referring to safety from outside people or hotel staff? Or, you are worried about the safety of the couple from each other? Well, it will be hard to generalise this. When unmarried couple share a room, they are expected to know each other well and should be confident about their safety from the other person. The couple should not share a room if they are not comfortable with the partner or worried about the sexual abuse from the other person.