I ordered mine a little over a month ago, but I think I remember a free-form text field where you had to indicate what you intended to use the SN for, I put in the typical usage: food preservation. Mine arrived around the middle of February, but I just opened it now. I'm a little surprised that the label specifically states, "do not give this drug to people with mental health problems!" and that by purchasing the product, you confirm you're over 21 and intend to use it for its intended purpose. I know that other people have stated that they are aware of people buying SN for other purposes, and I'm sure he's just trying to protect himself and his company.
I'm in the US and the customs declaration said it is an anti-corrosion concrete product.