Judges do understand the “hired gun” aspects of expert witnessing. A insurance defense motivated neurosurgeon must have used too many boiler plate testimonies in their courts. They threw him out on his ear. One judge reviewed 371 of his cases.

https://www.reviewjournal.com/news/news-columns/jane-ann-morrison/judges-ban-las-vegas-doctor-from-serving-as-expert-witness-in-2-cases/