crm_get_contact() returns junk instead of error

When I do:
$CRM = crm_get_contact(array('email'=>'foo@bar.com'));
when there is no entry in the CRM DB with email foo@bar.com, a CRM_Core_Error should be returned (or at least, one used to be returned).

Now, I'm getting a partially completed CRM Contact object, with the email field not set. I'm having to check field values before I can tell whether the get was succesful or not.

I first noticed this behaviour with Rev 3592, but it's also like this in the latest beta, Rev 3610.

Running

PHP4.3.10, MySql 4.1.11