This morning, a dev I work with flagged a server that was struggling. I logged in and, unfortunately, a bunch of "Scrapers" were hammering it, causing an overload. This dev is very sharp and understood the situation. He started extending the caching margins. I prepared a list of countries of interest and, using pf, blocked the rest of the world.
The load plummeted, and the client doesn't care about their products being visible outside of specific markets.
Shortly after, a similar situation on another server I manage (subcontracted, to be precise). I didn't know this dev and saw there was no caching in place, so I spoke to him and asked him to implement it. His response, sadly predictable, was that another one of his clients just moved to $CLOUD_PROVIDER and no longer has these problems, simply paying more when these "attacks" become more intense. I suggested he try enabling caching and thinking about their markets of interest. He's a positive person, so he agreed to give it a shot. A short while later, just by adding Varnish and some good VCL, the load dropped from 100% to 5%. Without any blocking.
He called me a little while ago, incredulous and happy.
It's always a pleasure to work with people who are willing to experiment, explore, and listen. With people who don't just follow the herd or ad banners, but who think for themselves. I've earned myself a walk outside the office now.