What insight can be offered to parents whose teenagers are suspected of experimenting with K2 Spice and other drugs?

This is a very difficult situation. Best to speak honestly to your kids and explain about addiction. I actually took a group of kids to an open NA meeting so they could see and hear first hand what addiction can do.

Years ago these were called designer drugs. Drugs were made that were chemically like banned drugs but weren’t the banned drug so they were legal.fentanyl was the base drug. All was fun and games until one compound in one of these drugs irreversibly bound with dopamine receptors in the brain resulting in advanced Parkinson’s Disease. Really not much new under the sun. But do speak honestly about drugs to your children.

We have been fighting this problem forever. IMO, we added to the problem with the so-called "War on Drugs."
Drug abuse should NOT be treated as a crime, period. It should be treated instead as a disease, an illness, which it is. If a child develops a life-threating disease, such as cancer, we would not put them in jail. Drug abuse is the same.
Drug dealers, those making big money off of drugs, yes! Lock them up!
Those who fall into the drug trap, no. Treat them!