Current doesn't kill silicon, voltage does. Example, you take an LED. It's a red one that runs at 2V. You can probably dump 3-4x that voltage through it without a resistor, and it won't care as long as the polarity is correct and it has adequate heat sinking. Now, this same LED has a reverse breakdown voltage. Many LEDs now days have native protection about double their nominal operative voltage. So for this LED, it can take upwards of ~4V reverse polarity. You give it 5V or higher in reverse, you will destroy the p-n junction.
This knowledge is what is used to design LED arrays which can run natively off wall power without any power driver circuitry.
V+ and GND are power supply rails, are you claiming that an external device can overdrive the computer (or USB chipset's) power supply without sending enough excess current through it that would trip the fuse?