Originally Posted by dasunst3r
Agreed, and here's why: Lithium-ion batteries have a relatively unstable chemistry and must be manufactured correctly with various types of protection. One way these batteries fail is to release a lot of energy in very short order (i.e. explode).
Example: My Curve's OEM battery: 3.7V * 1Ah * 3,600s/h = 13,320 joules of energy. It's no stick of dynamite, but ten bucks says that amount of energy released in less than a second could blow your hand off.
Point is: Lithium-ion batteries are pretty dangerous things. Only buy from trusted sources (not eBay).
A little knowledge is a dangerous thing. Ten bucks says it is impossible under anything close to normal conditions to release that energy in anywhere close to a second, even in a poorly-manufactured battery. Even if you shorted the battery, terminal-to-terminal. So the 'caution' is way overblown.
FWIW, I bought 2 eBay batteries for my Pearl used them for over a year (rotating occasionally). Normal life, never a problem.
And yeah, sometimes OEM batteries are defective too.