It's generally not a good idea for packages to routimely write in /etc.

Wouldn't it be better to move the /etc/fake-hwclock.data file to /var/lib/fake-hwclock/fake-hwclock.data ...

Hi Rick!

Normally you'd be right, but fake-hwclock is a special package by its
very nature. Its data has to be accessible *before* any filesystems
are fscked or mounted normally, so that it can set the clock before
fsck complains about things like "last mount time in the future".
Unfortunately, there is no guarantee of this happening if the stored
clock state is stored under /var. About the only safe place I can see
here is /etc...

Hi!

Thanks for the clarification.  I see your point.

Rick