I don't think there is nearly as much code review in open source projects as people would like to think. Then there is the problem of churn if the new committe

I don't think there is nearly as much code review in open source projects as people would like to think. Then there is the problem of churn if the new committers get confident and rewrite minor things, which is quite taxing on the existing committers. Wikipedia is a good example that a small number of people either have to guard their territory ferociously or else have everything rewritten. Now, sometimes a rewrite is in order, but in general churn is a major time sink for longer term committers and in fact one of the reasons they ultimately leave.