Comment 4 for bug 579804

:) I mean, what is the cost of writing 1G? As long as it's done in the background it shouldn't matter to the user (aside from using energy and generating heat). There is a small risk of the user trying to access the file until it's written but as long as that's visually indicated in Shotwell then they've been warned. I am sure if the tags are not written there will be enough people who will forget/not know to use Shotwell to do the export.

I'd say if you want to cater to both classes of users then you'll need the checkbox in the preferences.
a) Pristine mode to keep all info in the database only, generating a "(modified)" file for changes
b) Modify mode to update file metadata
And we'd default to the latter