They'd confiscate and destroy the bag. It's specifically California Penal Code section 653o that makes it illegal. It's a misdemeanor and carries a minimum fine of $1k and can go up to $5k. Here's a copy of the actual text of the code section:
653o. (a) It is unlawful to import into this state for commercial
purposes, to possess with intent to sell, or to sell within the
state, the dead body, or any part or product thereof, of any
alligator, crocodile, polar bear, leopard, ocelot, tiger, cheetah,
jaguar, sable antelope, wolf ( Canis lupus), zebra, whale, cobra,
python, sea turtle, colobus monkey, kangaroo, vicuna, sea otter,
free-roaming feral horse, dolphin or porpoise (Delphinidae), Spanish
lynx, or elephant.
Any person who violates any provision of this section is guilty of
a misdemeanor and shall be subject to a fine of not less than one
thousand dollars ($1,000) and not to exceed five thousand dollars
($5,000) or imprisonment in the county jail for not to exceed six
months, or both such fine and imprisonment, for each violation.
(b) The prohibitions against importation for commercial purposes,
possession with intent to sell, and sale of the species listed in
this section are severable. A finding of the invalidity of any one
or more prohibitions shall not affect the validity of any remaining
prohibitions.