Many pieces of audio equipment have two off / on switches… one on the front and one on the back. This is because many have some kind of hibernation or low power mode.
Given the question… we are not really talking about ending a listening session and turning stuff off.. but reaching behind or “shutting down completely a unit” before unplugging. So, you should “shut down” or turn off the rear power switch if there is one before turning off the power conditioner. Many streamers are very specialized PCs and don’t like power shut down. Most components are not sensitive… but not worth the chance.