I can't even imagine being able to hit the brakes hard enough to flip the back end up. Would probably be in a crash. Blue trucks's brakes work really well too. The rear of that bike is heavier than the front.
I used to do it that way. And when I get a proper front chock, I'll probably do it that way again. But with my $4 front "chock," pulling the bike rearward would tend to pull that front tire out of my "chock." With the fronts pulling forward, the rears pulling rearward, the fore-aft position of the bike is close to neutral. And out of the $4 chock it goes when exposed to undulations. All 4 pulling forward kept the bike against the front rail, and in the $4 chock. Otherwise, I agree with you.
It ran real good that way. No problems.