I think how you get on the curb is irrelevant, there can be a ton of reasons: you were tired, hungover, there was ice, rain, it was dark, a hot girl walking by, combinations of the previous, whatever, accidents happen...
Well,
you can prevent it by installing a strip of rubber hanging down from the back but visible in the side view mirror and then stop when it gets pushed by the curb. Alternativley you can install a movible blind spot mirror, and angle it right for this use (my method). The best way is to install a "skid plate" under the bumper like Audi did with their A6. Then when you go over the curb, there's no bottom lip to catch on.
You can avoid ripping your bumper off once on there by raising your suspension (if you have an air ride or coil-overs)
You can squeeze a piece of rubber/plastic whatever in between the bumper and the curb, then when you pull forward your bumper will be pushed up and out of the way.
If you're really under there, you can jack the car up, put something under the tires and then you'll be good.
At the end of the day the only way to really make sure is to avoid the situation. The curb isn't going to get lower (if you have a jackhammer in your trunk you could lower it I guess) so you'll need to raise the bumper or remove the lip it catches on.