I haven't heard that method that peter uses. The way I was taught by my stringer (whom I trust profoundly) was that the first string to cut was the centre main followed immediately by the centre cross (or both at once if possible). The idea is to try and keep the main strings and cross strings “balanced” for tension, as this is what keeps the racket in shape and at its strongest when fully strung, and should remain this way as much as possible when removing the strings. This works well even with extremely high tensions. I personally cut the strings in the “middle” – equidistant from the frame, but I think cutting diagonally is seen as a good idea (hence cutting a main and cross string simultaneously.

If a racket were left with 28lbs tension in the cross strings and no tension in the mains, I would put money on that racket shattering. And similarly if the crosses were all cut, but the mains were not. Not so big a deal at lower tensions I imagine, but I would still think it better to cut a main and a cross in quick succession. Start in the centre where you are furthest from the frame. Cutting the first main string at the very edge is dangerous because the frame will undergo immense pressure.

However, everything I am saying is what I was taught, and the reasons are the ones I was given (he knows more than me I presume), and could be wrong or misinterpreted!