Dropbox is a wonderful file-sharing tool which I use with my students (they have no choice).
Mostly they share their project files with me, which ensure its backed up to the cloud, and sometimes I share papers with them from my collection. This had become easier last year with a simple control click to enable sharing.
However, sharing folders has no granularity in permissions – when I use the “Share This Folder” option in Dropbox, I am enabling full access sharing. and my students can edit, remove and even delete files! There is no middle ground.
They are a careful lot, I have backups and there is a 30-day revision history to correct errors so its pretty safe still. Still, best avoided by simply using the “Share Dropbox Link” option instead. This makes files read only.
Are you sharing files correctly?