Based on recent experience they are blocking the first row of F and some Y middle seats until they are needed. Despite what the press releases say several recent flights were full in F 16/16, and mostly full in Y. I have also seen the GA moving Y passengers not traveling together in order to social distance. Brewdog11 said it best, "onboard social distancing is route- and demand-dependent". They work to provide distance when able but will also fill a plane if the demand is there. I also experienced an A319 being swapped to an A321 because they need more seats in F and Y. F went out 16/16.