And that is the thing that goes along with what I said about reactance voltages. High SWR can cause really high reactance voltages to appear on your tuner even with only a few hundred watts. Power ratings are made assuming the impedance is such that the voltage ratings of the components is not exceeded. As for throwing a switch wbile transmitting....well you don't throw your tansmission into reverse with stopping first so why would you throw a bandswitch before you stopped transmitting?