I think the best way to get the answer would be to text the question to the scheduler.  However, in my limited experience with Agencies, I can tell you that the web builder person may assume that someone is going to work the following week. Then on Monday or the first day of work, the girl calls in sick, misses a flight, has family issues.
I am not at work today due to family issues. Other excuses include: Parents getting old and need care, kids get sick, tired of driving in rush hour traffic, tired of working, just plain tired, and sometimes hung over.
Pick one. cough cough.