I have 2 sets of siblings as both sets of parents started with one child, went on mat leave and came back with both kids. It is a greater financial liability so I add an additional clause in my contract. My notice period for people leaving is 2 weeks. For siblings it is increased to 4 weeks to give me more time to fill the spots. I still only ask for a 2 week deposit so as not to discourage parents from signing up if they have some financial restrictions doing so because obviously a 4 week deposit for 2 children would be the best part of $2k.

I do not offer a sibling discount as like most others have said, I have 5 spots and its actually much more beneficial for me to not take siblings on at all to reduce liability and 5 spots is 5 children regardless of whether they are related or not.