When flying this past week, I was stopped by security and they checked my Android tablet for bomb chemicals and it tested positive, three times! Fortunately they let me through after much talking ... I almost missed my connection.
My suspicion is this: I use the tablet to step through the instructions in the assembly guide, and I think I got some of the acrylic glue on the back of it (I see a clear "spot"), and so it must somehow be the case that the acrylic glue has some chemicals that these bomb-testing machines are looking for.
The test they ran on the tablet looks like the one in the pictures here: http://www.cnn.com/2010/TRAVEL/02/17/tsa.hands.swabbing/