Yes, grabbing brakes will stand the bike up; but we're not talking about braking; we're talking about decreasing or increasing throttle (speed) mid-turn. You don't believe me? Next time you go for a ride find a nice, long constant radius turn, pick a constant speed, and then roll off the throttle
without changing anything else; the bike will tighten up it's turning radius; and the converse is also true.
Don't take my word for it...go try it out.....