Actually I was hoping that it could always execute in read/write mode when I have my "development hat" on.
Then, I could switch into read only mode to listen to music.
That way, I would avoid waiting for any switch between modes (whether I do it or the player does it).

Yes. In unix, programs have to have an execute bit set before they can be run. Otherwise they are considered data.

That was the main reason why I was switching to r/w mode because you cannot change the bit in r/o mode. However, I can see other reasons why one might like to be in r/w mode at all times.