Uhh... I've used lifelines since I started knitting, but I have never heard of that method.
The method used most often and the best for the knitted material is to thread a finer yarn on a yarn needle and then put it through the stitches on the needle. Then continue knitting and if you have to rip back you won't go further than the lifeline. I suggest doing it to the stitches on the needle rather than a row that's already knitted so you don't miss a stitch. this method also makes a lot more sense for a large object like a blanket.