I had a band break once, though I'm pretty sure I know why. I've always tried following John's technique of folding the shroud lines inside the chute, but that particular pack I think things were loose enough inside that when things started to pull in air the strap tried to pull the CR further up the chute, and broke the band in the process. So the main came out at apogee, and when I recovered the rocket the band was broken and the pin was missing (so it clearly released at the appropriate time). John sent me a replacement pin and a long piece of the cord, I've been intending to both make a longer loop for the CR attach itself, and considering the rest of it to make a 'backup loop' to hold the pin in case the band breaks (just so that I don't lose the pin), but I am a bit afraid that this extra loop could create a tangle, so I haven't actually done it yet. I do now do a final 'tug' on everything to ensure that the shroud lines are taught with there still being slack on the CR's strap before I wrap my chute protector 'burrito'.
I had a second flight (most recent Snow Ranch) where I thought the band had broken again, the main was out at apogee, but when I recovered it the band was intact. I continue to have terrible luck with AT motor ejects, this was an undrilled J180T-L where the motor charge went off at 6.8s after burn-out instead of the expected ~14s, and I guess the early ejection pulled the chute out of the band without breaking the band, unless it somehow tricked the Chute Release into releasing early. Either way, no parts lost (and I've flown that band 3 more times already), just an early main parachute deployment, leading to it spending about 4 minutes in the air and landing about a half-mile away, still easily found thanks to an Eggfinder TRS.
But lots of other totally successful flights, including two more yesterday on my Nike Smoke, a J401FJ and a J1520VMax, both flights to ~4800' with the main releasing at the expected 500' and short walks even though it was pretty breezy at ground level.
