Thanks Dejan. When I asked this question, data security plans did not exist. It seems that "background backup" was accidentally added and set by default in 8.1, but it has reverted back to normal behaviour in versions since then.
I would like to know what BackgroundHALShouldPause does, and how to use it. While it's listed in the HAL Primitives report, it is not used in source code and it doesn't appear in the LMS HAL...