AT&T has a new product and they insist that the router/modem be connected to a grounded outlet. I know the grounding and why we need it in good detail. Besides the obvious, why do electronics need the EGC in order to operate properly?
Ever touch a refrigerator that is powered but not safety grounded? Rub a finger on the metal to feel a tingle? That 60 volts is leakage from 120 volts. Leakage currents that may be microamps. Without a safety ground, those microamps create 60 volts.
Same is often true of electronics. Besides the obvious - safety ground - those leakage currents must be harmlessly conducted. That 60 volts has a potential of creating other problems - operational or reliability.
That safety ground does nothing for surge protection. Wires that are too long, too many sharp bends, splices, bundled with other non-grounding wires, etc cannot properly conduct surge currents. Safety ground has problems such as high impedance which is why that wire is a safety ground (or equipment ground) and not earth ground.