Transit visa

If I fly from Luang Prabang, Laos to Kunming and have another stop in Guangzhou after Kunming before heading to JFK and any parts of my journey get delayed or cancelled prior to me leaving before 24 hours, what would I do? Would I be fined? The 72 hour free visa shows you can only stop in one city in China, and I will have been in two. Would it be worth it for me to get a Chinese Transit Visa just to be on the safe side in advance and save myself any potential headaches?