Toilet Plume Risk: Does flushing with the toilet lid down protect us from disease?

I have a friend who brought this to my attention and so what follows is the results of doing my due diligence. My sources are listed at the end.

(Hat Tip to commenter Esprise Me at http://msgboard.snopes.com for asking similar questions back in 2006.)

1. Does aerosolization occur as a result of flushing a toilet?
   If not, then this discussion is over and no action should be taken.
   
   
2. If toilet aerosolization occurs, does this mean organisms are thereby introduced to faucets, mirrors, toothbrushes, etc.?
   If not, then this discussion is over and no action should be taken.
   
   
3. If toilet aerosolization routinely introduces organisms throughout bathrooms, does it pose a significant health hazard?
   
   
4. If aerosolization occurs and DOES NOT pose a significant health risk, then this is one of those basic germ facts o' life--you come into contact with them every day, and they're not gonna kill you.
   Then this discussion is over and no action should be taken.
   
   
5. If aerosolization occurs and DOES pose a significant health risk, would closing the toilet lid actually do anything to reduce the risk? (It's not like it forms an airtight seal!)
   
   
6. If aerosolization DOES pose a significant health risk would any risk reduction be significant enough to justify badgering people who share my bathroom to start closing the lid when they use the toilet and thereby potentially damaging my relationships with them?
   
   
   a. If not, then discussion ends and action should be taken privately. If you choose to act as if this is true anyway and also cannot resist the urge to share then it should be done in a manner that neither expresses nor implies that this behavior is reasonably expected of others (it might be UNreasonably expected, but that goes with the territory of sharing spaces with intimate partners and is OK as long as it's acknowledged as an unreasonable expectation).
   
   
   b. If so, evangelize this hygienic revelation!

Conclusions 

Based on a Snopes discussion from 2006, an episode of MythBusters from 2004, and a New York Times article from 2012 (linked below):

1. Aerosolization does occur from toilet flushing.
   
   
2. Organisms are routinely introduced throughout bathrooms (though there may be other explanations besides toilet aerosolization as the Myth Busters found out in their experiment).
   
   
3. That aerosolization occurs and DOES NOT pose a significant health risk is the conclusion that was reached by Mythbusters.
   
   
4. IF aerosolization DID pose a significant health risk then closing the toilet lid would NOT reduce the risk. This is a conclusion that a commenter at Snopes.com claimed was reached by Mythbusters, but the episode in question did not address it at all. However, given that they had control toothbrushes in an area separate from the bathroom and still got fecal coliform introduced, then it is probably safe to say that the bacteria have other transportation options besides toilet aerosolization. 
   
   
5. The New York Times article says the scientific evidence is non-conclusive. “[A] new review article finds that there are as yet no direct cases of proven infection, and that the possible risk is still unknown.”
   
   
6. Evangelizing does not appear to be warranted since the advocated behavior of closing the lid before flushing would appear to have little or no effect on reducing the introduction of organisms throughout the bathroom since that seems to occur independent of toilet flushing.

Source URLs:

http://msgboard.snopes.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=35;t=001754;p=0

http://www.nytimes.com/2012/11/27/science/the-possible-peril-of-the-toilet-plume.html?_r=0&adxnnl=1&adxnnlx=1394301895-otTQUNyi8Avf7RAKxj5Utg

http://www.discovery.com/tv-shows/mythbusters/mythbusters-database/fecal-matter-on-toothbrush.htm

http://www.discovery.com/tv-shows/mythbusters/videos/surprise-toothbrush-minimyth.htm?_ga=1.99286686.1437047395.1394314992