JHunter- I've never arrived in SJC from NRT, but after you clear customs, don't you just take your bag and leave? Or do they bus all the passengers and cleared bags to terminal A,

I sure wouldn't recommend leaving a bag on a carousel with the hope that an airline will lock it up. Someone could take it by accident or it could be stolen. It is unlikely AA would assume liability for it if you failed to make a prompt lost baggage report -and 5 hours later isn't prompt. In addition, baggage liability for international itineraries (including the domestic portion) is extremely low, about $650 per bag.

Save the grief- see if there is storage service at SJC or have the bag checked to LAS.