User with Read-Only permission can write

Question

Hi,
I have two Macs on a local network. I am sharing a folder on Mac-A and would like users to have read-only access to it. It is important that users cannot modify the data in this folder.
On Mac-A:
Selecting System Preferences->Sharing->File Sharing, I added the folder to "Shared Folders". Next, I added the user account "bob" and assigned Read-Only access. User bob is not an admin and shows up as a "Sharing Only" account under Accounts.
On Mac-B:
I connect to Mac-A as user bob and I can see the shared folder. I then am able to create and delete files in the "Read-Only" share. I've verified using File->Get Info that user bob does indeed have only read access.
What am I doing wrong and what can I do to enforce read-only access?
Thanks!

Answer 1

Maybe your Mac-B user account has the same (short) user name
as your Mac-A user account. Matching user names or short user names
could make the Mac-B account able to Read & Write to your shared folder.
Because I think you can log in with short user names to a server
as well. I guess passwords should be matching as well,
and perhaps the user ID's (System Preferences -> Accounts
-> right-click on user) also?
Cheers,
Vincent Verheyen.