Why don't EJBs (particularly Entity Beans) have an isDeleted() method

[J Mark Birenbaum]

Can anybody provide a nice rational explation as to why Entity beans don't have an "isDeleted()" type method on them.   Someone else asked me that today, and all I could come up with was that it would be silly to use an EJB thats gone.  Either you have it, and it's OK, or it throws an exception when you try to use it.   Unfortunately, "it's silly" wasn't a terribly convincing arguement.  If someone can provide a clearer explanation (or better yet, a reference to a paper that describes it), I would appreciate it greatly.   Thanks!