**The airline is liable.**  
According to the Montreal convention the airline cannot disclaim liability via their contract of carriage or other terms and conditions. As in this [analysis by the US DoT][1] (not USA specific):

> We have become aware of tariff provisions filed by several carriers
> that attempt, with respect to checked baggage, to exclude certain
> items, generally high-cost or fragile items such as electronics,
> cameras, jewelry or antiques, from liability for damage, delay, loss
> or theft. A typical provision found in carrier tariffs and disclosed
> on carrier websites states that the carrier does not assume liability
> for loss, damage, or delay of “certain specific items, including: ..
> antiques, documents, electronic equipment, film, jewelry, keys,
> manuscripts[…] money, paintings, photographs...”
> 
> Such exclusions, while not prohibited in domestic contracts of
> carriage, are in contravention of Article 17 of the [Montreal
> Convention][2] (Convention), as revised on May 28, 1999. Article 17
> provides that carriers are liable for damaged or lost baggage if the
> destruction, loss or damage” occurred while the checked baggage was
> within the custody of the carrier, except to the extent that the
> damage “resulted from the inherent defect, quality or vice of the
> baggage.”

Compensation is limited to 1131 [SDR][3]s which today is approximately US$1500.


  [1]: https://www.transportation.gov/sites/dot.dev/files/docs/webnotice_04012009.pdf
  [2]: https://en.wikipedia.org/wiki/Montreal_Convention
  [3]: https://en.wikipedia.org/wiki/Special_drawing_rights