Passing observation
Sometimes even urban legends spawn associated legends of their own. Whenever someone references the "1 million attendance" on parade day factoid, someone in-the-know counters that some Caltech scientist some year back did the math of bodies per square meter and disproved its possibility.
But no one can remember his name, when it happened or how they heard about it.
UPDATED: Your humble narrator is schooled in the comments.

Ask Larry Wilson, your public editor.
thanks, gar-dog. todd, my man: it wasn't at all obscure. it's in the clip files three meters from your desk. long story short: my stepfather, al hibbs, caltech physics ph.d., 21 years ago mentioned to his friend jack smith, l.a. times columnist, that there was no way 1 million people could fit on the parade route, as per the longtime ppd estimate, which it turns out was borne out of an old santa fe railway croud touter. jack said, do the math. he did. no way, it turns out, that a million could be there. jack mentioned it in the times. then our city hall reporter -- your predecessor -- john fleck asked al to expand on it. using very simple arithmetic that gave every benefit of the doubt -- i.e., it wildly exaggerates in favor of more people -- al and john showed that at most 500,000 people including the grandstands are ever on the parade route. that's it. we ran a front-page story. everyone said we were just being pillish. we were just telling the truth. no one likes the truth. they like round numbers. lw
Thankfully over 1/2 a million people were spared the horror of the Beijing '08 float.
I actually still have that story someplace facinating stuff.
Thanks for showing up on Saturday guys - hope you guys enjoyed it.