I disagree, aluminum wheels can crack by overtightening the spokes (the eyelets do not really prevent that, as even seen frequently in older Marvic rims). I think the first LBS could have easily set you up for that failure, when overtightened the spokes by his truing. The rim might have been bent from that first ripped spoke and rather then bending it back first, the first LBS might just have trued it by spoke tightening only,which can easily create small eyelet cracks which then propagate, when been ridden on by a heavy rider.