Some can be set to return to last state, be it on, or off.
Most amplifiers these days have "soft" power switches. Momentary switches that trigger logic to turn on the SMPS or a relay which activates the main power transformer (they often have a small standby PT for remote power up etc). They may or may not work in that situation.
Old school amplifiers with real power switches can be left on and triggered at the wall point, a remote relay switch or whatever you like. That is, unless you have one of the rare birds where there is an interaction in the physical switch that activates a turn on delay/surge protect using additional staged contacts or ganged switches and an inline resistor/relay to prevent huge turn-on currents.
My main power amplifiers (and entire system) are switched via a relay operated power strip. Party because of the turn on surge on the switch contacts, partly because I like to be able to turn everything on and off by RF remote when I go to bed. And it saves a ton of wear on switches that don't need it. Also, if I fall asleep and my partner doesn't want to wake me, she can switch off everything without laying a finger on the HiFi. And I like watching the lights dim/flicker when I turn it on.
