Unfortunatley that is usually the way with relief teachers- the problem is that they get booked in advance, so where they may be available on Mon, they may be booked else where for tues etc- relief teachers are in very short supply (at least here in WA, and I live and teach 20 mins for Perth). As for the work, that is quite usual, if a teacher hasnt left any specific work then the relief just gives them things to keep busy, and while I used to try my best to include some maths, english etc, I had no idea what level the children are at, what they hve done previously, what the teacher had planned etc. Even when I know I am going to be away and leave work for a releif, it is not usually exactly what my normal program would be- partly because another teacher doesnt know what is in my head, what I am trying to achieve from a certain lesson, and what I am assessing, and partly because when I am teaching specific things I like it done my way and like to know it is done properly.

ETA- If I am away from work sick, then I am usually sick sick, so dont feel I should sit for hours at my computer typing lesson plans and emailing them in for a relief teacher- especially when the person taking my class is a qaulified teacher and being paid nearly $300 a day to be there, I expect them to be able to come up with 5 hours worth of lessons to get through the day.