It's always interesting how people define what is a thing. He's got a good definition but he should take it a step further. Expand it to anything that you have that you would feel bad if you had to replace. The digital clutter weights on your mind just like physical objects (files on the macbook, email in gmail, all of it).

Also although he list the items that he'd be pissed if he lost he'd probably be a lot less angry them a lot of people if he was robbed. Simpler and cheaper to only have to replace 15 items.