Steve, small amounts of clipping are harmless and generally inaudible. Yes, other than hearing the distorted sound if it was heavy and prolonged, examining the waveform on an oscilloscope is the way to detect flattening of the wave tops.
As a practical matter, as Mike pointed out above, you're not going to have significant clipping taking place with an amplifier as powerful as the one in the 7200 if the sound level isn't dangerously high. Again, using an SPL meter, such as the digital model from RadioShack, is a good way to monitor actual sound levels which are experienced at the listening position.
