I don't see any issue. Amp power switch kills all electrons to the amp. Heck, your house is always connected to the electrical grid without any problems.

I have a habit of leaving my guitar chord plugged into the amp, and leaving the amp chord plugged into the power bar. What do you think? Amp is always turned off.
I'm not concerned about an electrical issue. Just wondering leaving the plugs in does anything to the amp connection itself over time like oxidation or a weakening of the connection where the amp cable plugs into amp, that type of thing.
Interesting... and now you had me thinking! We have a 3 bedroom house - smallish at 1300 square feet. I can count at least 31 vampires that are plugged into the house. AC powered clocks, numerous audio and video components, timers, computer and its peripherals, chargers and backup batteries, phones, etc. I am not counting the 3 fridges! The 2 biggest watt-suckers at idle, are our 2 set-top cable boxes which suck around 70 watts each.On a similar topic I use these around the house for vampire type equipment. A notorious one is my toaster oven. It consumes 4 watts sitting there doing nothing more then powering the LCD screen (and microprocessor). Darn thing doesn't even have a clock. I power it up for the few times we use it during the week and the rest of the time it sucks nothing.
View attachment 12690
Interesting... and now you had me thinking! We have a 3 bedroom house - smallish at 1300 square feet. I can count at least 31 vampires that are plugged into the house. AC powered clocks, numerous audio and video components, timers, computer and its peripherals, chargers and backup batteries, phones, etc. I am not counting the 3 fridges! The 2 biggest watt-suckers at idle, are our 2 set-top cable boxes which suck around 70 watts each.
I got the same one. Very useful gadget!I bought a "Kill-a-watt" years ago that measures the current draw of AC devices.
I have a habit of leaving my guitar chord plugged into the amp, and leaving the amp chord plugged into the power bar. What do you think? Amp is always turned off.