School learning verses actual experience in steel crack repair. Drilling a hole to stop a crack was discussed in a materials class in college, roughly 20 years ago.
Some googleing brought up a couple results on the subject:
in airplanes -
http://www.mechanicsupport.com/metal_fatigue_crack.html
in highway signs -
http://www.ce.udel.edu/cibe/news%20a...hop/Dexter.pdf
about halfway through there is a formula for determining the size for a stop-hole diameter - rule of thumb is listed as diameter should be 1/3 the length of the crack - not good news for bike repairs.