We know that adult patrons who have fines on their cards quickly figure out the way around this is to get a card for their child and check out materials for themselves (the parent) on this fresh, new no-fines card.  

To clarify, we aren't talking about not letting a child check-out because the parent has fines, this would only resolve the one-time problem of a child getting a card when the signing "responsible" parent/guardian has fines.  

On the one hand, it feels wrong to deny a card to a child because his parent/guardian is irresponsible.  On the other hand, allowing someone we *know* to be irresponsible sign as the "responsible" person seems foolish.

Obviously, figuring out to what extent this is a problem is difficult.  We think it happens once a month or so, but we couldn't really put a quantity to it - and certainly not a dollar amount.  

Does anyone else do this?  Any suggestions?  Any considerations I'm missing.