At the moment, there are certification programs for that. Many manufacturers participate. They supply the information and support training to ensure that vehicles are repaired in accordance with manufacturer's specifications. It works very well.
I'd like to raise another point, however. After a collision, the dealership doesn't necessarily have what it takes to make body repairs. In such instances, the dealership signs an agreement with an independent body shop or with one of our members for things like body or rust repairs. There are never any problems from that standpoint, and the person carrying out the repairs always has access to the manufacturer's standards for the particular vehicle to be repaired. As I mentioned, many manufacturers work with us and provide us with that information. Unfortunately, some do not, and that's where a problem arises.
As for warranties, provided that repairs are made in accordance with manufacturer specifications, the warranty is approved.