Honestly, I can guarantee my shaft it's not a problem, on a genuine Grenadier it's a lifetime product, you just have to change the UJ sometimes and it's a really common UJ , spline are 3 times longer than genuine, impossible to kill them
BUT , in one year and one day if you broke it ??? Or how can I be sure you don't abuse it ? How to be sure you don't have 10" lift , 42" tyres, how to be sure you don't do races with it ?
So yes of course you have a one year warranty , but for USA it's David responsibility to know the customers and to say me what's happened, it's why i accepted to loose a little of money and have an intermediary person in USA