I can't claim to have tested it at speed, and it uses el-cheapo k-mart bike components that were never meant for the added loads so your concern does have merit.... although it's not a bike that would normally be ridden at high speeds, especially with a decent load onboard. Personally, I'm confident it won't break, but I won't offer that guarantee to anyone else.

If money isn't a concern and you want a quality bike I'd go for a BD and good components.