[hibernate-dev] [ORM] Event Listeners: what's the consequence of not implementing Serializable correctly?

As you might know Hibernate Search is implemented mainly as a complex Event Listener to events from Hibernate ORM. The Hibernate ORM event listener contracts "suggest" that such event listeners need to be Serializable, but it seems our listeners is not actually serializable since some time. It appears to be serializable and there's quite some complexity to make it happen, but I'm realizing that the tests are incomplete and it's unlikely to work in practice. Yet everything seems to be fine: no tests failing, no people complaining, nor bugs have been raised. Does someone know if there's a realistic use case being broken? How would a reasonable test look like? Thanks, Sanne