I'd disagree with the article and say the biggest threat of the RTG's is not being used by terrorists because a dirty bomb isn't all that effective with that amount of material, however, a bystander digging into one and having fun with the material could be a serious problem. Like the Goinia Incident [0].
Then again. It's kind of a funny thing to worry about with all the unexploded ordinance that's around most countries, even the U.S. I was just out sailing in the long island sound last week and my girlfriend thought it extremely odd how many unexploded bombs pockmark the navigation charts.
