I bonk all the time, per the Australian meaning.
As far as hitting the wall - I only did that when I was running 165-190 for three plus hours, two times, about a year apart. And I learned my lesson - felt like being hung over for about a day or two. I follow a couple of simple rules to keep it from happening-
1) On the road I drink 1 oz. per mile up to thirty - over that double it - over 100 miles double it again. Mtn bike - 20 the first hour 30 there after.
2) After 2-3 hours I eat - and I don't stop untill the ride is over.
Of course I use common sense - if it's super hot or cold I adjust accordingly.