g8000-g9000 input panel label?

Hey guys, what does the red label say on the pic below?

Why are the phono inputs capped? Any disadvantage to not capping other than dirt?

From my AU-7900

"IMPORTANT
Do not insert theses pin
plugs into jacks other
than PHONO.
Inserting them into certain
jacks will cut sound off."

They're shorting plugs used to reduce unwanted noise on the phono input. Don't know if they're needed but they seem to come with amps that have two phono hookups.

The unused phono input 'open to the air' can pick up unwanted noise that may find it's way into the 'in use' phono input - hence the shorting plugs.