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I use various third party apps that sync files to dropbox (or scan folders for things like media files). These apps have edit permission to my ENTIRE account, even though they really only need access...
I agree 100% with what you are saying. I just discovered this and find it more than a little disturbing. I was considering using Dropbox to sync an encrypted password manager file, but now that I see three other apps I use will have access to my entire Dropbox, I'm not so sure I want to do that. The decisions on what files an app has access to should be up to the account owner not some lazy app developer.
I guess one solution is to create a new, separate Dropbox account that is used only for a specific app. That is inelegant and probably not what Dropbox wants people to do.