Judging from the comment of the commit implementing the
"--no-optional-locks" switch,

https://github.com/git/git/commit/27344d6a6c8056664966e11acf674e5da6dd7ee3
​
, the switch was implemented exactly for background refresh in "tools like
IDEs or fancy editors".
I.e. for mitigating this particular bug! Now we only have to use this
switch in our "fancy editor".