The new version control system in 3.0.0 works differently than the 2.5.x multi-dev system, which I feel is leading to some confusion here.
In 3.0.0, saving is not the same as committing. For instance, you can save all you want in an airplane (without internet). Then, as soon as you have an internet connection, you can commit your changes (which include all documents that have changed on your PC since the last time you committed) to the team server. Your local changes never get propagated to the team server or your other colleagues unless you explicitly commit.
That being said, as Bas noted, deploying to the cloud directly from the modeler explicitly asks you for a revision. This is so that versions in the cloud are always traceable back to a revision. This also means that you can't deploy uncommitted changes directly. A workaround (which we don't encourage for the above reason) is to hit F7 (or 'create mda/deployment archive' from the menu) and create an MDA. If you select Unversioned in the popup, it will explicitly use the model as you currently have it on your PC. This will include all documents that you have saved on your PC, but not necessarily reflect any changes that have been committed to the repository by your or others since you opened the modeler.
All that being said, version control is still something abstract and we've noticed that the way the modeler/cloud/team server are working together isn't super intuitive. We'll keep on trying to improve this and make it as clear as possible.
From my understanding deploying to the cloud does not automatically commit anything. Deployment on the cloud is always done with a revision in SVN and never with a local copy. This is because a local copy could always have been changed so cloud deployments are always SVN-based to ensure you can always figure out the exact version of your application that is running in the cloud.