Hi Mike,
I assume when you say move around you mean taking it home? I just checked my Modelsim license and the 800m clause applies to any license, nodelocked or floating. However, I would say that as long as your Modelsim dongle is nodelocked, insured and you work for the company that paid for the license than I don't believe Mentor will complain about a license breach if you take it home. I can be 100% sure though since I don't work for Mentor but I assume they have more important things to do :-)
Regards, Hans.