dblink causing import errors

Our developers like the dblink modules, so I have installed it into the
template1 database. They also like to import old database dumps after
creating new databases with dbcreate. But then they get irritated by the
error messages saying that the dblink functions already exist, because
these functions are in the old dumps, but dbcreate already copied them
from the template1 database. Also, some scripts which copy databases
break or create unnecessary error messages because of that. Are there
any best practices when using dblink to avoid these issues?

-- Christoph