This has me very curious now so I looked up how a 3s Li-Po is wired:
If I'm understanding this correctly, balance leads 1 (ground) -> 2 would give 3.7v, 1 -> 3 would give 7.4v, and 1 -> 4 would give all 11.1v. Right?
Correct. Now if you connect balance leads 4, 3, and 2 you will have shorted cell 2 and 3 = smoke!