You can't control the patient; you can however influence how other providers prescribe to the patient, by blowing a patient's story out of the water, or educating/making a provider aware of their actions or treatment from the specialist's perspective.
We are 100% responsible for making reasonable attempts to communicate with other professionals in the coordination of care. We all know things fall through the cracks and just sending over a note does not always do the job, sometimes it takes a phone call.
At the end of the day, there's really no right or wrong. I lean toward the autonomy of the patient and PCP.
Patient (with capacity) doesn't want to take my professional opinion? Cool, 'Murica, free country.
PCP wants a BZD consult from me but doesn't want to read my note? Cool, no one reads my lengthy, lovingly crafted notes either. But at least skip to the A&P like everyone else. English, do you read it mofo? I assume, yes. And appropriate use of BZDs isn't some mysterious concept mastered only by psychiatrists. If I was concerned, I'd leave a message to the PCP, "Saw your referred patient, recommended BZD taper, see my note."
What's right, best, and practical are debatable anyway. If I chase down every PCP benzo rebel or referred BZD patient who tells me to shove my plan where the sun don't shine, then I have less time for patients who actually want help and will see less patients. Who's to say the best answer isn't slapping the PCP and locking up the patient for a quick inpatient BZD taper? Arguably, society would benefit and more lives would be saved if we radio-tagged every non-compliant psychotic patient or severe opioid user and blow-darted meds at them q1 month.