Malte - if you want your code to break, then put in an error statement, *not* code that may work or may not work or may make a developer think somebody else put it there on purpose.
It is much clearer and a lot less time-consuming for the person doing the port if he knows what is supposed to happen. If you write this:
error;
// This code needs to be ported from the file foo.sql
than:
insert into ....
which may fail with a bogus Oracle error message. Maybe worse: it does not fail, but it has weird side effects.
The bottom line is: don't commit code to a non-private branch that has not been tested (without a warning and/or commitment to fix the bugs yourself) and if you want to indicate future work, write that in prose, not in code which may or may not work.