First off, this is obviously a sticky topic. Every conversation is controversial and speculative.
Second, I don’t really see a lot of legitimacy to the “gateway” concept. The vast majority of people use some variety of drug (caffeine, alcohol, nicotine), and that doesn’t really reliably predict “harder” drug use. Lots of people use marijuana and that doesn’t reliably predict hard drug use. Obviously, the people who use heroin and meth have probably used cocaine and ketamine, and weed before that, and alcohol/caffeine/nicotine before that, but that’s not really a “gateway” pipeline so much as paying through finer and finer filters. As far as I know, the concept has fallen pretty heavily out of favor with serious researchers.
In light of that perspective, I think you have to consider the goal. Is your goal to punish people, or to reduce the number and severity of victims? Mine is the latter. Personally, I think this sort of thing peels off many more low-level offenders to low-effort outlets than it emboldens to higher-severity outlets. I think this is ultimately a mental-health problem, and zero-tolerance mandatory reporting (while well-meaning) does more harm than good.
I’d rather that those with these kinds of mental issues have 1. the tools to take the edge off in victimless ways 2. safe spaces to discuss these inclinations without fear of incarceration. I think blockading those avenues yields a net increase the number and severity of victims.
This seems like a net benefit, reducing the overall number and severity of actual victims.