any memeber can leave, it's just that if you are lvl 90, the first two wave you don't get any exp at all, and if you are a lvl 70, you still get some good exp.
this is a myth, its just some stupid trick to get the highest level ppl to leave cuz they think they take all the EXP, in actuallity EXP is shared and ppl in the game ONLY affects the * to EXP modifier. its funny what noobs come up with. All you proof is in diabloii.net, ive read it ages ago.
I agree with blckshdwdragon. Ive told ppl in baal games its just bs i kinda tested it myself being partied with 8 and 7 ppl and still the same exp.....1 exp for skeles and watver exp for ravelers kinda the same.
I have never heard this either but I have jumped into games when its the third wave and it bad enough then trying to get people to party let alone leaving and asking them to party again.