Given that there are currently 655/5279 already private, no, they didn't jump the gun.

Edit: 1 minute later already 658.

Edit: 2 minutes later 661.

Edit: 2 3/4 hours later 840.

I'm clicking on some of them, and can still view the posts?

Do you have an example? I tried a sampling of private subs, none showed posts for me.

Oh never mind, I didn't realize that the mechanism was to go private. I thought that all the subreddits listed were already dark.

I mean, it has begun: https://www.reddit.com/r/diy

Just the title. The page itself acknowledges that the strike is scheduled to start tomorrow:

“These subreddits are going dark or read-only on June 12th and after. ”

looks like its a website monitoring the subreddit statuses with a handful of them having already gone private

Ah, my mistake. I wasn't aware some subreddits had already started, thought it was supposed to start tomorrow.

The fun has begun ;)

It's also tomorrow in some countries already!