That is actually pretty close to my expectation? Isn't it close to yours? Let's rewrite to remove the snark:
"We will transport your child safely from A to B, accompanied by our staff at all times. We expect it will be according to the itinerary provided but due to operational reasons, there may be changes, which we will attempt to notify you about"
And who knows, maybe they did try to call the mother? Everything in the airline industry comes down to checklists; I'd be surprised if there isn't one for this situation, and equally surprised if "try to contact the guardians" isn't on there somewhere.