On the other hand, society imposes all sorts of strictures that it imposes on civil behavior and that members agree to partake in. For instance, most people agree to silence their phones during a theater performance. I believe that people who give out their email address to others in order to be contacted also agree to return any missives within a reasonable amount of time. If they don't want to agree with that, don't give our your email address. I do not know how people feel about texts as I do not currently own a cell phone but I would imagine it is fairly similar.