Why do riders not take advantage of other riders misfortune
This compilation of articles on the subject goes into a lot of depth and sources some examples and opinions of some very notable cyclists themselves.
http://bfc.sfsu.edu/cgi-bin/unwritten.pl?Dont_attack_when_your_rival_suffers_bad_luck_-_Cycling

&quot;I don't know when it evolved,&quot; said Phil Liggett ... &quot;It's been a gradual thing, this so-called unwritten code. But now it is understood. You don't attack a fallen man.
&quot;The unwritten rules among elite bike riders hold that a rider should win through effort and talent, not through misfortune on the part of competitors.&quot;