>>>>You could therefore make the case that the employer is at least guilty of some degree of ignorance or negligence.<<<<
I think the nail has been hit on the head with the above statement. In my area a "so called" top 100 ENR inspection/testing company is using soils/environmental people as management (this particular branch) to bid on and manage projects that requires the use of qualified/certified inspectors.
Metals/NDT people are considered "nonprofessional technicians" with this company. What that means is that you could have 40 years of hardcore advanced welding/NDT experience, have every inspection certification available, and yet a 22 year old soils engineer (that likely thinks MIG welding has something to do with Russian jets) is considered management over any welding/NDT inspector.
As a result of this incompetent management (at this one particular office), they are using NDT testers in lieu of qualified inspectors. In other words, you take a lower payscale man, teach him to use a MT Yoke, throw a level II MT cert on him, and you got a "good to go" welding inspector. If he's over the age of 23, you can bill him out at senior inspector rates. Due to the fact that they are a top 100 ENR company,they are not being questioned by their clients.
Hopefully, the above scenerio is the exception to the rule for this company but I think INCOMPETENT MANAGEMENT PLAYS A LARGE PART in the use of unqualified/uncertified people.