Don't many passengers carry laptops/mobile phones with lithium batteries on airplanes all the time?
Yes, avoiding these batteries is about as hard as avoiding computers these days. They're all over these days, and usually don't cause any problems. And when they do, the batteries are either used in ways they weren't designed to or counterfeit batteries found in items like those too good to pass up internet deals like the $15 Magicshine clones.