Trying to restrict people from installing across a network or locally does not work!
Sequence of steps: Download ISO. Unpack ISO to local directory. Mount that directory on another computer. Attempt to install. Swear quietly. Copy directory to other computer. Attempt to install. Swear more loudly.
Download Daemon Tools. Mount ISO. Install. Smile contentedly.
It's worth pointing out that I mounted the ISO *across the network*.