To use POEM you need to have write access to your database. POEM is very well behaved and leaves no trace of its interaction, other than its metadata tables, but you may feel that creating tables in your database is too much.
POEM gathers information about your database and stores that information in the following tables:
A CourteousPoemDatabase deletes these tables during shutdown. You may have used POEM to modify the database, but you do not need to perform the cleanup step of removing the temporary metadata tables.
After you have accessed a database with POEM then it is no longer pristine, the possibility of it having been altered still remains, not least by your application, but there will not be a bunch of new POEM-specific tables left behind.