Another solution would be to just remove the battery and plug the laptop in. While this removes the portability, it is still an alternative solution.
Yes, they could still be removed in some cases, but its often not for the feint of heart and not something many people would want to undertake.
Yet another major regression in the state of computing since the 90s.
The article's solution is amusing and "cool" but not really secure at all. If you're worried about physical security of devices, don't take them to coffee shops.