Lipo charging bags are a good idea; they are a bit of an inconvenience, but worth the extra hassle. A bit off topic; but still relevant...I own a micro helicopter and purchased extra high end batteries for said copter. One day while charging all the batteries I noticed that a few has swollen, I decided best to set aside and replace them. On the trip to get replacements I noticed that my pocket I had put the batteries in was terribly warm. When I arrived at the store I showed the batteries to the owner and said me thinks these are in a bad way, you may want to put these in the metal container. He grabbed them noting how hot they were and gently tossed them into the safety container they use to dispose of batteries (just emptied that morning thank goodness) and when he tossed them into the container they caught on fire.
Now I ALWAYS charge lipo batteries in a safety bag, be it the helicopter or the e-cig batteries, I do however use the laptop in the standard way. I have heard that these bags are not the best of the best for safety, but they beat nothing. Should a blow out happen at least it is mostly contained in the bag and less likely to burn through the counter or floor. I have thought of making a safety container of my own using a fire proof safe and some fire proofing compound where the cord would enter just haven't found time.