I'm not sure I fully understand your reasoning.
I'm not sure cornering is something to be taking a look at after you hook a 5000 lbs trailer @ your car, unless I didn't understood what you mean with cornering.
The trailer have brakes so in fact the additional load that goes to the TV brakes are the loads you allow adjusting your braking sensitivity, am I wrong?
In the case of the Airstream guy he probably was over not only on the tongue weight but also on GVWR....
In my case, the tongue weight will be above but both the max. towing weight and the maximum weight of the TV (GVWR) don't....
So I don't think the brakes or handling of the vehicle would be off of the expected by the designer of the vehicle ....
I have the design maximum weights for each axle and could/will be adjusting the WD to be within the limits....
Am I wrong on the reasoning?
Country Mouse, have you measured your rig? Are you above the limits of your SUV?
Ricardo & Luciana
For a person may labor with wisdom, knowledge and skill, and then they must leave all they own to another who has not toiled for it. This too is meaningless ... Ecclesiastes 2:21