I’ve submitted a ticket to BCTC asking them to look into what happened to the link that used to appear on the PaperCut printing portal login page that gave users with guest accounts a way to log in and submit print jobs. For now, there is no way for guests to use their guest account to print.
In the Library Services wiki on the “Guest Printing” page there are detailed instructions showing how we used to have guests print. Until this issue is resolved, those instructions are now unusable. As a workaround, we can use our judgment to decide if and when to use our own printing accounts to help out our visitors.