After increasing visibility for PLAs, Google tests a carousel format on desktop https://www.twenga-solutions.com/en/insights/plas-google-test-carousel-format/
Referral spam has been a pesky little problem for people who like to compile accurate reports with Google Analytics. And it's been a problem for a long time.
There's an interesting post at WebmasterWorld about a "loophole" which may be giving brands the opportunity to buy their way to the top of Google's SERPs.
This is a significant issue, and I wonder that it's not getting the exposure it deserves. potentailly, there are many, many systems that may be vulnerable.