IMHO, the key is that we don't understand the real 游戏规则 of the b-schools in the US. There are tons of laws we are not quite sure. Of course, not understanding cannot be used as the excuse to be against the law.
How to know 游戏规则? Generally speaking, we get it from the formal documents. The American think their documents are clear enough. Unfortunately, we may encounter problems based on their instructions only since some commen sense they didn't mention.
Going back the topic of this post, can we accept two offers? Is accepting one offer the 游戏规则 of the b-school? It seems to be commen sense. However, I cannot find any evidence to confirm it after I have read thoroughly several offer packages.
All in all, the US is a completely new enviroment for all of us. We should be very careful before we get any trouble. This is a good suggestion from grandma.