First of all, they’ve been in cities all over the country for 3 weeks. Why the sudden hysteria?
Second, if you were making a bomb, would you attach it to an illuminated image and then put them in places where people would readily see them? Would you put the battery on the outside?
The funniest thing of all is that I mentioned to my wife the other day that they looked like Lite Brites to me and then later saw that the Wikipedia page says that they indeed are. Yes, Lite Brites. A toy from the 1980s. What’s next? Anthrax-laden Colorforms?