Apple is the worst offender by wide margin, because their phones are the most expensive ones and have the biggest sales (=production target). Add the fact that

Apple is the worst offender by wide margin, because their phones are the most expensive ones and have the biggest sales (=production target). Add the fact that the deadlines on product announcement and shipping are very strict, so the pressure on workers assembling iPhones is the biggest. Stress with assembly of other manufacturers' phones is nowhere near than that of Apple's. Samsung, I think, assembles phones in Vietnam, where labor conditions are better than in continental china.