At work we use this fairly old Tek DPO TDS3034 - quad channel 300 MHz 2.5GS/s scope.
I noticed that it gets very warm in standby, initially wrote this off as it feels like it uses a "real clunking" mains switch.
Then when unplugging it from the rear, I noticed it lasts about 0.5 seconds with no power, but when turning it off from the front, it dies instantly.
So I'm pretty sure that the mains switch is fake just like in the Agilent and just controls the REMOTE pin or similar on the PSU. But I'm not allowed to open it to confirm. Anyone else brave enough?