There have been a few news stories recently about laptop computer theft. Yes, you can buy a laptop lock, but be careful - some of them are super crummy, but they might deter the opportunistic thief. And be sure to lock it to something secure. In a hotel room without a laptop-sized safe, lock it to the pipes under the bathroom sink.

LabMice.net has laptop security tips that are geared toward IT folks, but aren't freelancers our own IT folks?

If you deal with incredibly sensitive data, you can get a token system like those made by Cryptocard. I first saw one of these used by a friend who works for an organization that had some data security issues a few years back. It's not cheap stuff, but it could be a bargain for some people.

I don't keep any data of any consequence on my laptop: it's all on my thumb drive, on my desktop, or sent to one of my email addresses. That way, if the laptop is gone, the files are not. If you need to keep data on your laptop, use passwords. They aren't perfect, but they are better than nothing.

One other thing: if you sign a contract with a liability clause, put client data on your laptop, and then the laptop gets stolen, you might have a big problem. Keep that in mind if you sign liability clauses and if you have any client data.