What are these?

[60bass]

I strongly disagree. I'm a flats player, and I like OLD flats. My newest ones are years old, and the oldest are more than 50 years old. They are not replaceable! If someone replaced a set of 10-year-old flats on one of my basses I would be very upset.

I would loan a bass to a very good friend, but making ANY changes to an instrument that's loaned to you without specifically asking about the changes first and getting clear permission to make the change is extremely rude.

^^^^^^^^
100% this