Diagnostic tests can help identify disease and its probability. Healthcare community usually recommends what is helpful; but for defensive diagnostic testing, it can be somewhat of gray area. In the current healthcare market, costs are opaque.
If people know their insurance cover includes everything (if under the cover at all!), then they tend to go with what their doctor is saying in terms of getting a test. However, the level of benefit, risk and cost influence a patient decision to have a diagnostic test.
