Should wagging (skipping school) to protest for more action to address climate change be punished with a detention?  Would facing a punishment like detention make the protest more meaningful?

Interesting questions, but irrelevant in my view.

Absolutely good on every student who participated in a protest for more action on climate change today.  The first step towards change is awareness. Whether you were there to skip school, or there to stand up for what you think is important, you helped bring awareness to the issue.

By the way, for another message to us adults from a younger generation see the video:  Dear Adults.