Traffic Signal Backpack

Some immediate observations:
1) a rainy windscreen would turn the signal into a blob of light
2) only good if you're sitting fairly upright
3) drivers would laugh at you and bully you
4) if they got even vaguely popular, drivers might rely on looking out for it and not notice proper hand signals (similar argument for flouro stuff no?)
5) the girl in the video doesn't even look around when she's turning off...

etc

1) A blob of light is a good thing on a rainy day. Still improves visibility.
2) A back pack could be designed to be less position dependant.
3) I doubt it. No more than they do anyway.
4) Not really. If would have to be so popular as to be adopted by more than 50% of the riding population, probably even more than that. Also, I don't wear fluoro and don't find visibility to be a problem. Visibility is about more than just what clothes you wear.
5) Relevant to the usefulness of the product how?

I agree with phi_pp, I wouldn't buy one either. I do like to see some people making an effort with design, espcially for cyclists, where so much stuff bought to market is dull and indistinguishable from anything else.