It is a very dangerous thing to do unless he is bi-amping his speakers, meaning his speakers have more than one pair of connections suitable for bi-amping. The outputs of the two amps will NEVER be equal and there may be high circulating currents between the amps, which may cause overheating and protection circuits to kick in.
Two amps into one pair of speakers
This is a newb question, but my friend has two integrated amps hooked up to his speakers, one McIntosh and a Prima Luna. One is connected with banana plugs and the other with spades. He said this will cause no problems as long as they are not both sending signal at the same time. Is this true. It just seems a little strange to me.
TaterMike