I already have a very small blender where the blades (maybe 1.5" long) are built into the bottom of the cup, and it doesn't come apart (big pain for cleaning, but that's another story). However, if I wanted to cut someone or something, I'd first have to fit it into the cup and get it to the bottom (does that make sense?). To me, that doesn't seem like a security risk, but my guess is that TSA might feel differently...