Upvoting an already trending post is the worst strategy when it comes to curation rewards. You'll only add curation rewards to the early voters while making a negligible amount yourself. The rewards algorithm heavily favours early voters.

Instead upvote great undiscovered posts, then spread the word around. That's the optimal way to maximise curation rewards. Or maybe strike a balance by voting early on a semi-established but not trending author, they will get some votes after you.

Of course, you're right to be concerned that few are aware of how the rewards system works and may end up piling the votes on trending posts in ignorance. Worse still, they might end up being the kind of casual voters who make less than 10 votes per day, and now suddenly have much greater influence due to the vote impact change.

I hope as a community we can curate responsibly. It'll need the right education and support.