With a frontal impact, such as riding into a wall (or an errant motor vehicle -- been there, done that, not recommended), the frame will generally bend before the wheel or the fork will. The damage will start at the bottom of the front of the downtube, as on your frame, manifesting itself on the bottom of the front of the top tube as well, in the event of a more severe collision.

I kinked my first Capo's top tube and downtube at the end of the butting when a motorist left-crossed me. I had the frame cold-set straightened at Rancho Park Cycles in West Los Angeles and got 6 more years out of it before the downtube began to rupture where it had been bent. MY safety was never compromised, and I was able to ride home very gingerly with a cracking downtube, but it was a little embarrassing to let some kid on a Varsity beat me up a 12% grade as I watched the crack form and propagate from the bottom of my downtube.