I like that idea! In both my husband's family and mine, I was the Designatd Liar to "the Moms".
For DH's mom, I saw her daily and the lies varied with the weather and her moods. The point of the lies were to keep her safe - "Hello, cab company? You are not allowed to pick up my mom at this address and take her to the Superstore. She has dementia and no money." "Mom, guess what? The cab company won't drive out here anymore!"
In my family, I was the only one brave enough to lie to my mom (she could shoot lightening out of her eyes). And both families were big Catholic families...what are the odds that I would be the DL for both teams? LOL
:)