If the algorithm recommends “buy now,” and the fare actually drops prior to travel, Google will issue a cash refund. In its initial trial, the guarantee only applied on travel booked between August 13 and September 2.

The feature is either a bold product move or a savvy marketing effort - or both, as the guarantee emphasizes confidence in the accuracy of its predictive algorithm.

And given how Google’s product suite is closely interwoven, it’s not that much of a leap to wonder if such a guarantee could soon extend to hotels.