I have one too! I can tell her parents spoil her and she is expecting me to do the same here but I don't give in. She wasn't here whole week and I found myself not saying "don't do this xxx, no claming there, don't touch this and that(she doesn't play with toys but explores my house, furnitures, cables, plugs etc.). Whole week was soooo easy without her. I've already replaced her as I don't want to have stressful days when she is here. And she takes so much of my attention that I can't pay attention to other kids. Couple of more months and she is gone. Yayyyy

Do whatever is best for you