I think you may be confusing the "hollowing of chest" with hunch-backedness. Alot of the Chinese styles emphasize the hollowing of chest to lengthen the reach of the bridges, and also allows the settling of the lower "kua". If you notice the dropping/tilting of the pelvis in coordination with the placement of feet and knees, you'll notice they are infact not "hunchbacked". One important thing I noticed, you need to watch how your chin is positioned while in stance. This allows better positioning. As long you are aware of that fact, I don't think you'll have a problem with having poor posture on a daily basis. Besides, most Wing Chun practitioners do not go around walking in combat position with hollowed chest Hope that helps.