I think it varies. Some companies are deeply concerned with ass covering.
I once worked for a US-owned company who had a policy that nobody could touch a system unless they had been on the training course and got the certificate for that system. It didn't matter how much knowledge or experience you had. You had to call in the guy with the certificate. More often than not, the guy with the certificate was a useless moron who would follow the procedure in their course notes without really understanding what they were doing.