I've said that mechanical systems will fail in every way possible, and even some ways that are a surprise. A friend took his Bellanca Super Viking up only to loose all oil pressure at altitude. The engine seized and he crash landed when a slight dip in the field turned the plane into trees (he walked away w/ a bruised arm). A certified mechanic had changed the vacuum pump, but had left the bolts finger tight when he went to lunch and did not torque them after he returned. The engine pumped the oil overboard. If a certified powerplant and airframe mechanic can screw up so badly, for sure a dealer can forget to tighten the wheel to the swingarm.