Originally Posted by Steve Huff
You could always call the USRSA (United States Racquet Stringers Assoc). As you have found out, some manufacturers (Wilson, Babolat) allow you to string from bottom to top. Yes, they are usually strong enough, and even if they aren't, Wilson and Babolat will replace them if they are still under warranty. But, you'll also notice that if you string the same racket 2-piece, they recommend starting the crosses at the top. Wouldn't you think that if it was the best practice to string from the bottom, that they would tell you to start at the bottom even when doing a 2-piece? I guess until you've seen a racket break from stringing it from bottom to top, you probably won't be convinced. Best practice is to start your crosses at the top.
I think it also depends on how you string the racket. Many people like to string one or two crosses with the short side. If the long is routed to the grommet closest to the outside main grommet hole I do think it is a good method.