I've had two (2) rear tire tube failures at speed. They were both in 2005, a day apart!!!
The first one, two-up, at 50mph on US 6 in PA. Got stopped fine and, though it was Sunday, managed to find a dealer nearby who opened his shop to replace the tube.
Unfortunately, he did something wrong--probably pinched the tube on the rim. The next day, on I-81 in Shenandoah, passing a truck at ~75 mph, the rear tube blew again. While I was able to cross over in front of the truck, to the right shoulder (he saw what was happening and braked hard), I wasn't able to then get the bike heading down the shoulder, and went off into some very large clumps of sod., where I lost control.
Did a low-side, then a high-side, which launched my wife and me off the bike---somehow crossing paths in mid-air.
Totaled the bike (an '02 Kawasaki 1500 Classic), but both walked away unscathed. Called a buddy in NC, who came and got us and the bike.
I don't ride tube tires anymore.
I might add that my wife hit hard on her face. I have no doubt she would have been injured without her flip-up helmet.
I don't ride without flip-up helmets, either
Currently using Nolans, but I'll be trying the new Shoei after Christmas.