No argument that corrosion (quite possibly caused be disimilar metals) between the housing and stator caused the crack in the housing, but I'm not convinced that it distorted the stator enough to grip the rotor, it's (the stator) made from laminated steel and is pretty resistant to compressive distortion, certainly in my case it was rust between rotor and stator that caused the problem. I've stripped a few more since I wrote the article and never bothered removing the stator, as James said the risk of damage during removal is high, all the ones that I have stripped have been cracked and each one has been revived by the method in the article.
Believe it or not the alternator pictured is still fitted to my car, the crack has got worse to the extent that a small section of the casting has broken off, but it's still working fine