Has anyone out here seen or written a paper/website on the security implications of tethering a corporate laptop to your PPC6700?

My assumption in this case is that a corporate user could tether their laptop and VPN into the corporate network. What would be some security concerns with this setup.
The most obvious concern that I see with tethering is that you don't have any firewall protection (unless installed as software on the laptop itself).
A secondary concern would be the security of the connection if using bluetooth tethering (even though it should be encrypted by use of the VPN into the corporate network).

Anyone have any other good security considerations?

Links appreciated.

W0lfm4n