Cough, ahem, well, it was also explained to me that there may be some systematic labor-related problems with construction quality in those buildings. Not exactl

Cough, ahem, well, it was also explained to me that there may be some systematic labor-related problems with construction quality in those buildings. Not exactly related to worker pay-rate, but the gist is that they tend to pour the concrete too wet (because it is easier/faster to work). This is probably because of productivity-based bonus pay for foremen. The difference in strength isn't enough to cause a building to fail under nominal conditions, but catastrophic failure is more probable in some destructive event (weather, earthquake, explosion, etc).