Currently, one can create multiple linked sub-organizations under a main billing organization, but having the exact same names. The below API command, run repeatedly, will create the same sub-org name with different orgId's. I believe this only serves to confuse administrators and makes management more difficult -- therefore, I'd rather have the API fail with "HTTP 4xx: Another organization already exists with the same name."

curl -s -X POST --digest -u "$ATLASPUBLICKEY:$ATLASPRIVATEKEY" \
--header "Content-Type: application/json" \
--data '{ "name": "MYORG", "orgOwnerId": "MYORGOWNERID" }' "https://cloud.mongodb.com/api/atlas/v1.0/orgs" \
| jq -r .organization.name