I am in the process of moving my wife to China_ONE_BAG_AT_A_TIME. Not the best way to go about it, but it works for me. As such I have been traveling with three bags with two generally overweight (the third being mine). My experience has been:
1. Avoid the sky caps. In the past several months it seems like they realize every time there is a problem UA cuts them lose. As such, they realize their jobs are on the line and they won't do ANYTHING for you.
2. Smile. CSR's generally are there to help you. To date I haven't been hit once (knock on wood) and that involves 14 trans-pacific YTD.