I can definitely see if it was jammed into a bag or wound tightly (got to be a pretty fine line there!) how it could happen, similar to how if I jam my IEM earbuds into my bag all the time I'd break one in no time I'm sure. But at least the larger chargers have those neat L shaped hooks that are supposed to encourage the correct diameter twist - I would have thought that'd be the saviour? Usually when I've heard of it or seen it it's at the MagSafe end and it's clear that the cord has been pulled backwards away from the laptop regularly - which to me is still a design flaw if that's how users are using them they should be altered. Having said all that - the amount of HP and co laptops I've seen with bent charger pins or squealing caps in their power packs is unreal and they're often more expensive than an Apple charger depending on the wattage.