Yes. But let's say they are both lying in bed together, but Mom and 1 yr old had been snoozing for an hour or more. She wakes up and says where are the kids?
Maybe Stepdad says they are probably outside at the chicken coop, I'll go check-----Then he comes back with a worried frown and they begin to look for them. But before they call 911 they decide they need to get their story together and be each other's alibi, just in case people get suspicious or blame them for negligence or something.
At some point, one of them might start questioning in their mind, what the other person was up to.