Imagine this...
You come into the possession of a USB memory stick. You think it has valuable information on it. Not your information, but valuable nonetheless.
You're smart enough to know it might contain spyware so you plug it into an isolated computer where spyware can do no harm. Then... Fab-a-dab-a-ZAP! Fizzle. Smoke. WTF?!?!
Your USB port is fried.
You inspect the stick more closely and pop open the cover. Someone has soldered all four of the output pins together! Grrr, a 100% short circuit.
Bad practical joke or brilliant security? You decide.
Did the owner safeguard the information (the solder can be removed quite easily) in case of accidental loss, or did the owner just set you up for a nasty surprise?
Removing the solder and analyzing the information on the stick might yield the answer.
Why do I mention this?
1. It is another reason to avoid USB sticks from untrusted or unknown sources.
2. It's a true story.
~Kevin