S.V.
We have that "favorite grandchild" thing going on as well, and we unfortunately only live 10 minutes away from my in-laws. My husband's youngest brother, who was the baby of the family had kids, and those kids are ho-hahed and babied so much it makes me crazy. Rules that have been rules of the house since the first grandchild was born (and probably before that) have been thrown out the window for these two "favorite babies." It is obvious enough that my daughter notices, and asks "why doesn't grandma ever have me spend the night?"
What makes me snort, at least to myself, is when the other in-laws talk about how bad these kids are; hitting, biting, throwing fits when they don't get their way, and I just think, well yeah, because grandma will literally give them anything they want, and change EVERYTHING just to make them happy.
Sorry, I know this offers very little value to you, I just had to rant.