[donaltroddyn]

The problem is that you don't know who has plugged in a death trap transformer about to explode into flames in the apartment below yours, not to mention the numerous other ways that mains appliances can be unsafely wired.

[icebraining]

I also avoid buying stuff that takes mains voltage. But is the risk that they'll "explode into flames" a real concern? All house fires I seem to read about are a result of other factors (stove burners not closed, heating devices near flammable stuff, etc).

[donaltroddyn]

You're probably right, but I used to buy cheap USB chargers from Amazon and Deal Extreme, and had a couple fail with visible scorching and melted plastic.