Hibernate: getReference returns a proxy without hitting the database

// Needs the whole customer row:
Order o = new Order();
o.setCustomer(em.find(Customer.class, 7L));    // SELECT

// Needs only the FK value:
o.setCustomer(em.getReference(Customer.class, 7L));  // no SELECT

find:         select ... from customers where id=7
getReference: (no query) then insert into orders (customer_id) values (7)

Touching any field of the proxy triggers the select after all.