The other day I was so desperate to go climbing, but I couldn't find a partner, so I ended up self belaying after googling and watching this video. I did check Petzl's site to learn that modifying Gri Gri and self belaying using it is prohibited.
I'm not a crazy, careless climber and when it comes to safety, I try to be as cautious as possible. I searched and read several threads on the topic, but yet, I'm not convinced why this isn't allowed.
Now a bit more detail on what I did: similar to the video, I tied myself in, and then attached the other end with Gri Gri to the belay loop. I only climbed a few really easy routs, so that I could be certain I can hold myself up while taking the slack, and did make knots in several points as I ascended.
I understand that Gri Gri is not an automatic device, but I have also never seen it failing (at least with the 9.8mm< ropes), and I also try a few small falls and they were fine, too.
I wouldn't make this a habit to practice all the time, but I'm wondering what the issue is with it, with the added knots on the way up? If it fails (no!), the knot will stop it, right?
P. S. I would not dare to do this outdoors, but only indoors on easier route on that I badly want to climb and there's no one around!