A friend passed this on to me, from the U.S. State Department site for Uganda:
American citizens visiting Uganda are advised not to accept food or drink offered from a stranger, even a child, because such food may contain narcotics used to incapacitate a victim and facilitate a robbery. In 2006, there were a number of reports of such incidents in the city of Kampala. Victims included the patrons of bars or entertainment centers. Similar crimes occurred on passenger buses. In 2006, an American citizen traveling by bus from Kenya to Uganda was incapacitated and robbed on the bus when the passenger accepted a sealed beverage from a fellow passenger. Expatriates traveling by bus to the popular tourist destination of Bwindi Impenetrable National Forest in southwest Uganda were also robbed under similar circumstances.
Sounds a lot like someone I know.