The Seattle Times has an article on who is responsible when items are stolen from checked baggage.
This focuses on a woman on a business trip who had an estimated $8000 worth of items stolen from her luggage after she had checked the bags at the curbside check-in point. TSA responded after some time & said they may re-imburse her for fair market value of the stolen items, but not replacement value. Among the items stolen were a video projector valued at $3000 & other business related equipment.
TSA has taken over the inspection of baggage & asks you not to lock your luggage or they will break the locks to get inside. Yet it seems they do not want to take responsibility for your luggage. This amounts to another reason you should drive when possible.