The standard excuse used by friends with kids to get out of work or leisure activities with anyone, but mostly their childless friends.
We have a monthly meeting at work that is supposedly mandatory but many people use their baby shields to get out of it.

I thought that my brother was going to be in trouble but since he had a kid, he uses his baby shield to get him out of anything, especially with Mom.
by Rainbow_Cheese July 25, 2011
Get the baby shield mug.
the invisible yet all-powerful shield that protects all babies the pictures of whom have been posted on facebook from any negative comments, no matter how ugly the babies really look.
A: look at this picture of her daughter - that is one ugly baby.
B: yea, but there are 10 comments underneath that picture claiming this is the cutest baby ever.
A: facebook baby shield at work again.
by wazupyo June 3, 2010
Get the facebook baby shield mug.
Use of babies in photographs to emphasize that one's relationship status is definitely not 'single', or, if one is single, see baby cock block.
See Facebook for examples of the Facebook baby shield.
by Alleycat420 June 4, 2010
Get the Facebook baby shield mug.