I heard a second-hand story about some team at Google who did this, and named the variable something like:

  I_ACKNOWLEDGE_THAT_THIS_CODE_WILL_PERMANENTLY_BREAK_ON_2022_09_20_WITHOUT_SUPPORT_FROM_TEAM_X=1

a year before the deadline. I would be mildly amused by adding

  _AND_MY_USER_ID_IS="<user_id>"