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Just wondering ...

Would it make sense to automatically save the project before any export ?

Well, I already do that automatically by habit. Save often, be happy. But I can imagine situations where this would be unwanted, like (been there) with projects so large that they need more than a minute to save, so that would cause unwanted delay especially in a pinch (like having the director waiting beside your desk, already whipping a foot). So don't make this mandatory, but it may work as an option (in prefs).

I totally agree with Slowtiger.