Bin books are gadgets and as such must be lashed to your corporeal being ready to receive the infinite scroll of your senseless thoughts in written form. And so, attach it to yourself. Tape a safety pin on it, stab a keyring through the duct tape binding. Whatever works.
When you are in the company of distasteful people be like Harriet the Spy and write something unfiltered and disparaging on one of the bin book’s grocery bag pages. Because offline, no pne can hear you think.