My first thought was that it must be joke. A dress code for a high school graduation?
In Denmark everyone is free to wear what he or she wants, unless a uniform is proscribed (police, army, hospital doctors and nurses, postmen etc.). In very, very few companies a dress code exists - even if it might be advisable to some degree to follow company "norms and culture".
Business suits have become seldom except for lawyers and accountants.

In ordinary schools, high schools and universities certainly no dress codes imply and not at any occasions.

We dress casual.

Greg

By the way, life goes on, despite of that. We have one of the lowest unemployment rates in the world.