They let plenty of lithium batteries through now, in electronic devices. AFAIK, notebook computers use lithium batteries. I have two types of lithium batteries for my current computer (Dell), and my last two (Compaq & Sony) also used lithium batteries. Sony at one point was having quality control problems with their lithium batteries, but I don't remember the details.

I think my camcorder also uses them, but I haven't had it out of the case in a year or two. I think Sony is big on lithium batteries for camcorders and digital cameras, but I don't currently own any so I can't say for sure.