I used to have my children in daycare in St Catharines before I moved and I did receive a sibling discount. I don't personally offer them, but I think it depends on what other people are doing in your area. You need to stay competitive, but also feel good about the money you're making. I hate taking on siblings, but it's almost impossible not to. Some day's I feel like I should charge more as they are a much bigger risk financially.