Just seen one today that got a report.
Guy selling 3 batteries. 2 look in good shape, but the 7.4v vapex lipo (black) is dangerous.
Wires cut short, re-soldered, Heat-shrink not fully covering + on battery exit.
Swelling, Knackered heat-shrink insulation on battery, Burn mark on the deans.....
There is only 1 place that battery should go... and it's not in a gun.