mtry, I found this interesting article:
http://www.meyersound.com/support/papers/amp_power.htm
From the second last paragraph:
"Meyer Sound refers to the average power during this 500 milliseconds as“true burst power.” Peak power output should last at least 100 milliseconds in order to be useful for music reproduction."
Given that the limited space in a receiver including HK's, I doubt there will be enough capacitors in them to sustain 500, or even 100 msec of those claimed high instantaneous currents. Whether it is 10, 50msec or longer, I don't know, may be someone should ask them.