Recently flew SAT>DFW>LHR>BCN originating on AA in SAT changing to BA for the rest. All BPs had PreCheck which we smiled at since there's no PreCheck in LHR. On the return which originated on BA the opposite was true and no BP had PreCheck on it. We've never flown on two participating airlines on the same PNR so can't speak to whether or not PreCheck would appear on all. Kind of think it wouldn't as many of the domestic airlines are not part of the same alliance and non-partner airlines don't usually or necessarily share FF and profile information.