I treat a lot of backs with a mixture of appropriate mobility, core strengthening, Back hygiene emphasis, improving the aerobic capacity of Backs, breathing, positive thinking, pain control…. blah blah
I have a lot of clients and suggest methods to fellow trainers. I am however not a doctor. I  do talk to a lot of spinal surgeons, back researchers, GP’s and others with interests in “LBP”.
I frequently argue points with them. I don’t, however, ignore them. I do not believe myself to be superior to them. I do often see that we frame our thought processes: we automatically put  limitations to our evaluation  of the client. Evaluating the client is key.
You must listen to them, and watch how they move. If someone ends up in a surgeon’s office, they should do the same. Is there a saying along the lines that, if all you have is a hammer, every problem presents itself as a nail.
So 2 points,
1) if you are a one trick pony (” “stretching is the answer,” “cutting you open is the answer”) do  try and consider other options (if you cannot  nail some metal to  someones spine  in less than 8 weeks, why not  suggest  a therapy in the meantime. It could work!
2) As a fitness Instructor or “PT”  remember your place: every back client should   seen their doctor 1st. You  and they need to screen for “red flags” . Also, ask questions.  If  for example, someone comes in with a weaker leg maybe its something more serious.
A  report that appeared in the Spine  “Primary extraosseous Ewing’s sarcoma of the lumbar spine presenting with left leg weakness” is an interesting point according to this report
“A 7-year-old boy presented to the neurosurgery clinic with left leg weakness. Enhanced multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) were performed. MDCT images revealed a mass with minimal contrast enhancement that extended into the left L3-4 foramen and psoas muscle (figure 1). MRI images revealed a mass that was isointense on T1 weighted (T1W) images and hyperintense on T2- weighted (T2W) images compared with muscle (figure 2,3), with homogenous enhancement after contrast administration (figure 2,3), consistent with a nerve sheath tumors”
In short, work with doctors, suggest and help BUT don’t tell clients to avoid them ( don’t make the pester them either)