Given the hassle and expense of actually attending interviews I don't see what is wrong with a quick email to clarify a point. I for one would be pretty upset if I forked out airfares to attended a job thinking there was (for example) no weekend work only to find out that you work every weekend!
Maybe companies could be a little more specific in their ads to. The days are gone of there being a rumour of a job and 500 applications appear on your desk! If you look at ads for other industries it's all about what the company can do for you. Many HR practices in aviation are absolutely archaic and maybe it's time things started to change.