I've never used the StreetPilot 7200, but going by the nuvi I have with the Truck setting will route you exactly like I've claimed: across bridges with low weight limits, under low clearances, etc. Even
CoPilot will do just that as well - I've had it happen. Right now there are no true truck specific gps programs/devices that I know of that can be trusted 100%.
Hopefully we'll see something soon in the US. NavTeq has released data for Europe that is truly truck specific (google "navteq transport"). However, I haven't seen anything from them yet for North America. When they do have the data available, I'm sure we'll start seeing programs/devices that truckers can trust to not get them into problems.