Everyone has to arrive at the time stated in the booking. If you can't be there on time, you must contact the SISC Filekeeper as soon as possible for approval. It is not allowed for anybody to arrive more than 24 hours after the SISC event starts. Keep in mind that you must contact the SISC Filekeeper in any case if you are going to arrive late.
You are committed to stay for the whole time you booked (except for Weeks 31 & 42). The reason is that late comers or early leavers break up the camp spirit.