It is worth remembering that for every 1 horror story you hear about a snapped headstock, there are 1000 or more other Les Paul owners that will never break a headstock.

Sure, most Gibson/Epi' headstocks are a bit weaker and more prone to breakage than most others. Partly because once the truss rod channel is routed there is very little wood where the headstock angles backwards, and partly it's because they're typically made from mahogany which is relatively short grained compared to a species like maple (like how particle board is easier to bend and snap than plywood, since it's lots of small pieces that just pull apart instead of longer layers that can flex before they break). That said, it's not something to be too worried about since it usually takes a fair amount of force directly on the headstock to cause a crack/break, which is extremely unlikely to happen if the guitar is packaged properly.