Originally Posted by
jrkmsp
I thought more about this. The most likely reason they're banned in the CoC, but in practice let aboard, is so that if they're damaged, Delta doesn't have to pay to repair/replace.
They are not banned in the CoC. In fact, there is a specific exception made for them. You can absolutely check them at the ticket counter free of charge.
From the CoC:
F.
Acceptance of Fragile, Perishable, or Precious Items
1.
Items Deemed to Be Fragile, Perishable, or Precious
The classes of items listed below are deemed to be fragile, perishable, precious, or otherwise unsuitable as checked baggage and will not be accepted as baggage,
except as set forth in this subsection.
...
d)
Infant Items
Fragile items for infant care,
including without limitation strollers and car seats.
(the bolding is mine)