The only completely safe way to do this is to have a detached work tree in your Dropbox folder and your repository outside of it (i.e. set GIT_DIR and GIT_WORK_

The only completely safe way to do this is to have a detached work tree in your Dropbox folder and your repository outside of it (i.e. set GIT_DIR and GIT_WORK_TREE, or provide --git-dir and --work-tree/core.worktree). That way each machine can automatically sync uncommitted work tree changes, which avoids the "push a crummy commit because I'm leaving work / boarding a flight / on a boat" problem, but you still use the conventional Git mechanisms for transferring objects between repositories, which avoids the "I'm afraid of conflicting refs / repository corruption" problem.