You could write predicates over non-existent columns:

  root=> SELECT * FROM t
         WHERE definitely_not_a_column = 4;

  SELECT * FROM t WHERE 4 = 5;
   a | b
  ---+----
   5 | 6
  (1 row)

  System.out.println(((Integer)4).compareTo((Integer)5));
  > -1

So it's SELECT FROM t WHERE true;

Now, let's get busy blaming Jepsen for using the tool wrong.