right solution for orphaned nodes ?

I have review system with node reference relationships between products and their reviews. Node referrer is great and I use it for finding products that don't have any reviews, just checking if field is empty.
I need to manage orphaned nodes solution in case product node gets deleted or unpublished.
Is node referrer good solution for managing orphaned review nodes in such cases ? What would be best way to do it ? What about hook_nodeapi op 'delete' or workflow-ng module ?
I read somewhere that nodeapi 'delete' hook operation is activated after node is already deleted - so accessing deleted node data (such as node referrer field) in it is impossible - is it right ?