Indeed. She was seated within a few feet of where her dog was stowed.
Cats have been known to be packed and shipped in a van and arrive days later in fair health.
Did her dog have any known pre-exisiting ailments? (Perhaps already discussed)
By the way, in the landmark United Airlines ejected passenger case, it was on a Republic airlines flight with Republic crew operating a United sector. A United gate agent requested the passenger be removed. Airport security, not United, physically removed the passenger, but hey, don't let facts get in the way of your epic saga.
Many, many passengers have been known to over-sedate their pets for a flight. i.e. "if two pills are too many, three is just enough".
I am not a United Airlines apologist but given they carry 150 million passengers a year with a fleet of over 1,200 aircraft, statistically they will have some noteworthy incidents.