Electronic – DVI Shield pins

For the shield to be effective, it requires as low impedance connection as possible to your shield ground. I think those recommending resistors, or not connecting it to ground at all, or strictly talking about your digital logic ground, and assuming you have a separate shield ground. If you have a metal enclosure, this will be your shield ground. At some point, your digital ground must connect to your shield ground. For EMI reasons, this single point should be close to your I/O area. This means it's best to place your USB connector with any other I/O connectors around one section of the board and locate your shield to logic ground point at that location. There are some exceptions to the single point, rule, if you have a solid metal enclosure without any apertures, for example, multiple connection points can be helpful. In any case, at shield to circuit ground connection, some may recommend using a resistor or capacitor (or both) but rarely is there a reasonable reason to do this. You want a low inductance connection between the two to provide a path for common mode noise. Why divert noise though parasitic capacitance (e.g. radiate it out into the environment)? The only reason usually given for such tactics is to prevent ground loops, but you're talking about USB, ground loops most likely won't be an issue for most USB applications. Granted, such tactics will prevent ground loops, but they will also rend your shielding all but ineffective.

In an ideal system, the shield will not radiate (or pick up) and EMI. As soon as I see an ideal system we can break out the Campaign, as I haven't seen one yet in 25 years in this business.

The floating (battery) ground has no real influence over the problem-- well, at least no more influence than anything else.

An important thing about shields is that there should normally be no current flowing on that shield. Any current flowing will likely be radiated as EMI. The mistake that many people make is that they connect SHIELD directly to a GND pin of the same connector. That's not correct. SHIELD of the cable should be connected to the the metal chassis of the box, and GND should be normally connected to the ground inside of the PCB it's talking to.

I'll also note that EMI is a hugely difficult subject that is often more art than science. This answer just barely touches the surface, as we don't have the time or space to give this a comprehensive answer. But I suspect that you might not want the more detailed answer anyway.