Microsoft did something like this almost a decade ago. https://techcrunch.com/2012/09/06/bing-it-on-microsoft-claims-21-users-prefer-bings-search-results-over-

Microsoft did something like this almost a decade ago. https://techcrunch.com/2012/09/06/bing-it-on-microsoft-claims-21-users-prefer-bings-search-results-over-googles-in-blind-test/ https://techcrunch.com/2012/09/06/bing-it-on-microsoft-claim... https://en.wikipedia.org/wiki/Microsoft_Bing#Bing_It_On https://en.wikipedia.org/wiki/Microsoft_Bing#Bing_It_On It was marginal, in favor of Bing, though I don't think they did extended experiments with individuals.