The reason this works is because only a few would face hardware issues, so while there would be a few unprofitable accounts as a result of hardware issues, the

The reason this works is because only a few would face hardware issues, so while there would be a few unprofitable accounts as a result of hardware issues, the majority would be just fine. It's the same reason stores accept returns and don't go broke because of it; only a few customers actually return a purchase.