If you (as the airline) did what the rules where that everybody else follows and the FAA mandates and the baby dies you can argue you did everything correctly and the rules are at fault.
If you however go your own special, non-FAA-approved solution, typically the burden of proof that this special solution is at least up to par with existing certified standards is on you, the airline and if a baby dies it is on you alone to defend that solution.
Meaning from the standpoint of an airline there is not a lot to gain, but much to lose if they do things outside established standards.
This may sound idiotic, but it also prevents other "creative" solutions where airlines sacrifice safety willingly to spend less money.