Comment 11 for bug 858957

So your rationale for disabling this feature by default is that when
saving the reading position of your book in order that you can continue
where you left off, you may accidentally spoil the book for your
mysterious friend who finds himself continuing where you left off?

That's a pretty weak objection. It is a fringe case to begin with, and
made yet more unlikely by the fact that it is really easy to just... go
back to the start of the book, unless an even more unlikely coincidence
happens and the exact saved location has an actual spoiler which is
unlikely in my experience.

Claiming that an "ebook-viewer" has a misleading name if it also
modifies the book, which it doesn't as it merely stores additional
information inside the book like a number of other document formats, is
just silly. There is no rule of etiquette or expectation that a "viewer"
is fundamentally incompatible with modifying the file. You are making an
arbitrary differentiation that exists only in your own mind and was
devised solely for the purpose of defending your claim right here, right
now. But if you truly believed that, then users should not even be
allowed to *opt in* to such an "untruthful" program behavior.