From his Facebook feed today:
A petite bump and a slight nudge getting off the Métro in Paris and
bam — wallet gone. OK, I admit, it’s my fault…I wasn’t wearing my
money belt. And it cost me. I went back to the hotel, referred to the
emergency section in the appendix of our Paris guidebook, and set
about canceling my credit cards. I lost my driver's license, two
credit cards, and some money.
The irony makes this just a bit funny. But seriously, if you're in a high-risk area like the Metro then you have to be on guard.