On a related note, I am traveling back from the US to Canada and I brought one hoverboard battery pack for my Carvepower rig. I had it as carry on and pulled out on the tray in case TSA wanted to inspect it. It just went through without issues. I had some documentation in case I was asked about it. I guess it is better to be prepared than not. I bought two packs and decided to only bring one through in case I would lose it. Now that I have one through, I hope I will have the same success when I bring the second one through on a subsequent trip to the US.
"Doerksen admitted that the second iteration of his product, called Onewheel Plus, sells out as soon as it is stocked. I commended him on this happy problem. It retails for $1500. The original version sells for $1300 and is just about sold out; he won’t be making any more of them."