Since oxymorphone and naltrexone are similar in structure, seems a risk a broad-range morphine test could register a false positive. I imagine the worst like when a cop faced with an unknown pill shakes it up in their roadside kit. Or a more thorough opiate urine screening that includes naltrexone in the assay and having to explain to an employer why you are on an opiate antagonist (if you obtained medicine from a doctor, you are protected by HIPA and the results don't leave the lab).

Any real world experiences?

I think the easiest way to find out would be to buy one of those home test kits and pee on it. I would think it would light up the strip!

By the way, "Brando's got what plants like!" Indeed!!!