We both have grown DC, and now we both have DGC. His eldest DGC is now early teens, but I remember when they were little and wanted something they knew they couldn't have, they'd ask DH, and he would (knowing it wasn't allowed) say, 'Oh, you'd better ask Grandma if you can have/do that' I would then become the NO person, and he'd just shrug as if it wasn't his fault!! It used to drive me mad, and we had many an argument about being on the same page, regarding our grandparenting roles! Things got better and he agreed that this was totally unfair on me, and more importantly confusing for his DGC. So, years later, more DGC come along, and immediately with his youngest DGC, the exact same cliches came out, so...I turned the tables! My DSGC asks for sweeties the parents don't allow, DH says 'Yes, if Grandma says its OK' and quick as a flash I say, 'OK, you can have as many as you like, if Granddad said yes!' My DSGC immediately grabs fistfuls of contraband sweeties, DH later takes sickly child home to mummy & daddy, who suss by state of their DC face and clothes, Class A Disallowed Sweeties have been consumed, and DGC pipes up with, 'Grandpa said I could!'.....result! He doesn't do it anymore!
Just thought I'd share that example of how conniving and clever SM's and SGM's sometimes have to be!!! 