^^^ Uhh, yeah, I'd say that might attract some attention!
The regulation seems fairly straight-forward, and the chart at the bottom was particularly helpful. You just have to pay attention to whether it's an installed or uninstalled ('spare') lithium battery, whether it's a lithium metal or ion battery, and whether it's over or under 8g of equivalent lithium content. As it says all cellphone batteries and 'nearly all' laptop batteries are below that level, most of us should be fine. What you have to watch for are extended-life rechargeable lithium batteries, as if you have several lithium-powered items you may exceed the combined 25g-of-lithium maximum they have imposed. And note that for lithium metal batteries (as opposed to lithium ion batteries), only those lithium metal batteries under 2g are allowable for transportation. If they're lithium metal batteries with over 2g of lithium, they're not allowed in checked or carry-on, and whether installed or not.
They clearly prefer you to carry the devices-with-installed-batteries in your carry-on baggage. Given the types of items that use lithium batteries (cellphone, cameras, laptops), they're the types of things one rarely places in checked-luggage anyway.
If you're a professional using large, extended-life lithium batteries and want to take several spares, you might run into trouble. But 'Joe Traveller' carrying a few spares for consumer-type devices isn't going to be terribly inconvenienced.