Since almost all paywalled articles are from the WSJ, the Economist, or the NYT, this shouldn't happen to you very often.
The links are just huge wastes of time. A prominent tag attached to the article would be ok, but in the absence of any other feature to avoid these time sinks, it makes sense to flag the articles to save others from additional wastage.
- Just don't read the article.
- Subscribe. If you can't/won't afford it, then see above, or see below.
- Search for other sources of the information. And post them, it adds to the discussion. Most articles worth taking up space, particularly on paywalled sites, are worth that space in other venues. Almost nothing is exclusive, not after a day anyway.
In the WSJ case, I've noticed that yahoo often prints the article verbatim.
And many ads are paid per view, not per click.
Of the flood of links posted to /newest the paywalled links are nowhere near the most problematic.
Yes, over time you learn things.