Hi Brett Governanti,
Me too faces this issue , Data Reviewer go for all records even though select Selection set or Current Extent
but I found one option , I am not sure it will work for you or not , because it is sometimes work fine with my RBJ check list .
When we Start a Session go to Advance - Default Checks - unmarked Invalid geometry checks, because it is the default check when we start session it enable automatically , what I am thinking it may cause to check rest of the records for validity ,
Let's check it ,
if you found something new kindly let me know ,
thanks