Heard on the radio the other day that POTUS is doing the same thing. A couple members of Congress are doing the same to show that they are willing to accept some of the pain the feds are. Seeing as they cannot be compelled to do this as their pay is set by law, it is nice to see that at least some are willing to shoulder some of the discomfort.
In the case of political appointees, it's hard to say. In some cases, they may take a serious hit in pay just taking the appointment. I understand the late Admiral Watkins only did one tour as Energy because it was costing him major money each year to do the job. I think it had something to do with his not being able to draw his military pension while he was Energy. Not positve, and that was 20 years ago.