And how do you imagine that it would happen that Dropbox would randomly trash the contents of your files? Lots of ways. Suppose they tried to implement a 3-way

And how do you imagine that it would happen that Dropbox would randomly trash the contents of your files? Lots of ways. Suppose they tried to implement a 3-way merge system (a la git) to resolve conflicts in your synced files. It's easy to see that going terribly wrong if they implement it incorrectly. It's proprietary software as a service. That means they could conceivably make a breaking change like that without even notifying you, the user, and cause data loss.