Does anybody use Scrivener Desktop and iOS together?

Is there no way of warning that the project is open on an iOS device with unsaved (un-synced) changes?

Sync is just a fancy way of trucking data around, like you might more manually do with a thumb drive, right? A much more risky to use, but more convenient transfer technology. If you do not use it. If you do not copy your project back to the original computer, how is it going to know anything about the state of something going on, on a completely different device?

Is there a way to autosync the iOS project or is it left purely to the user having to manually sync every time before exit? This seems fraught with opportunities for error.

Please refer to this post for settings you can enable, or allow to run over cellular.

As for why there is no open/close detection with iOS, as I recall that notion is very complicated on iOS, where software shuts down if you stop using it for a spell, so even while the project is open, it’s state is essentially identical to when it is closed. But even if it were feasible to distinguish between open and closed, you’d still have to somehow communicate that fact (the Mac/PC versions use a lock file that syncs along with the project).