A wheel will fracture long before the studs break, most are grade 8 or better IIRC.
You would think so, but to support Arcticsteve's point about studs breaking with non hub-centric wheels, we broke several studs on one of our Ford Windstars when using some replica BBS rims. At least one per season would break off in my hands as I twirled off the wheel nut. We got rid of the wheels and, voila!, the problem went away.