Sinerio: Baby is crying in the crib because he woke up and wants to see everybody. Baby is bored and needs some attention.
Mom's Solution: Send in the three or four-year-old into the room to entertain the baby with talking and playing. Before you know it, BOTH baby and toddler are distracted. Baby is still in the crib as literal captive audience to the entertaining sibling who is talking and playing on the floor. (Baby-safe toys are also important here).
Aha! Kudos to my mother! That was a smart plan!