Of course, that wouldn't be the case when the pulling isn't completely in-line with the socket (although you can exert quite an amount of strain on a MagSafe cable by pulling it out sideways). I think it's too simple to assume that MagSafe wouldn't suffer from this problem.
The explanation given by the parent post rings true for me, certainly I've had these kinds of splits in plenty of cables with traditional "strain-relief" on. I think I'm going to stop unplugging things by tugging the cable. :)
I always remove the connector by tilting it first, instead of pulling. In fact I think there was something in the manual about this - though I can't find it at the moment.
But it doesn't say anything about tilting.
It looks nice, all shiny and aluminy though...