> People have free will, if they want to do something they would regret later, it's still their right.

Then this minor frictional measure is the very least of your worries. For a start, any given pharmacy has an entire pharmacopoea of compounds that people are kept away from for their own good. Not to mention liquor licensing rules making landlords cut folks off at a bar if visibly drunk etc. And guard rails to stop people climbing to high places. And ... preventing people from doing stupid shit in the moment is everywhere in our societies.

There are a heck of a lot of things I'd put higher up my list of concerns than "may have to visit two shops if wanting to kill myself"