How do you distinguish between the gas pedal being down due to being stuck versus the gas pedal being down due to someone stepping on it? In either case the sensor is going to report that the gas pedal is down. All the software intelligence in the world is going to have a hard time distinguishing between the identical inputs of PEDAL_DOWN and PEDAL_DOWN.
You could have more intelligent sensors, perhaps, but then that's no longer a software problem.
There is a final solution: make sending spam more expensive. Spammers will only spam so long as it's mind-blowingly wealthy. If you can raise their operating costs and bump them down from "mind-blowingly wealthy" to only "obscenely wealthy", they might switch to other lucrative immoral industries like manufacturing printer ink.
What this does is increase the computational power required to generate a spam email. The method they described sounds like it's self-learning (just hook it up to a spambot "oracle" and it'll figure out the new template), so spammers will likely have to abandon the use of templates altogether. If you increase the amount of computational time required to generate spam, you decrease the amount of spam sent and really decrease the profitability of it.
We keep pushing the requirements for spam further and further up the computational totem pole (or Chomsky hierarchy, if you will) and you get closer and closer to a point where spammers are going to have to create strong AI to write spam. If they fail, we don't have spammers anymore and if they win, well we have spam, but we also have strong AI! Win-win, I say.
Next up, the researchers want to evaluate 500 vets, alongside 500 civilians, to further validate their findings.
It sounds like a case of "well we didn't have enough grant money to do this study properly this time around, but our results still look promising! I'm sure some more grant money would give really conclusive results! *waggles eyebrows suggestively*"
Understanding is always the understanding of a smaller problem in relation to a bigger problem. -- P.D. Ouspensky