Who owns what you throw away?

An interesting angle on the dumpster-diving craze comes from Singapore. A judge has previously ruled that confidential information discovered in the trash cannot be used against someone, but the issue is to go to appeal.

It seems to me the burden is and should be on the person discarding information to take care to make it unreadable, for example by cross-cut shredding and burning. It seems fair to me that it's their fault if they fail to take sufficient physical security measures to protect the information.