access control for periodicals - does my plan makesense?

> So my plan is to put some logic in hook_nodeapi.  If
$op == 'view', and 
> the
> user has not subscribed to the node in question, I can
do something like:
>
>    $node->body = t('Sorry, you have to subscribe to
view this.');

You could instead use the 'view' op in hook_access of the
node type. As with 
all ops of hook_access, it overrides what's in the
node_access table.