So I have a group of users for which the group permission on a document library is set to Read. There are other groups with other permissions, but there is no overlap in terms of group members. Despite the document library having only the Read permission for this group, users are still able to download the Excel document and click Edit Document here: http://bit.ly/11cIsAt
Now, they SHOULD see the following message: http://bit.ly/V2TAKr
but they're allowed to continue editing and save back to Sharepoint. So for some reason, they are allowed to write/contribute with only Read access. These users are not SCAs/SCOs anywhere on the site and there is no member overlap with groups that have more access. Any ideas? Sorry for linking to images...would have posted them in text but I don't have enough reputation.
EDIT: The answer! The Read permission level was edited to be able to "Edit Items" in "List Permissions." By default, this is not checked. However, someone checked it and so users with Read access were able to edit items in the Document Libraries.