Per this blog article, there is now a way to return randomized search results:
https://community.crownpeak.com/t5/Developer-Blogs/Search-G2-updates-CORS-headers-and-random-sort-or...
Unfortunately, this does not work in combination with paging through the results. The results get re-randomized with this solution every time you fetch a new page of results, even when using the same sort seed value. This significantly limits the usefulness of the feature for our purposes.
An option to preserve the randomization by specifying the same sort seed would be ideal.