Re: forgetting CVV
not something I've experienced. But if it's a possibility, I'm sure there are plenty of ways to have it noted for oneself, but not available to anyone else. From a bogus phone number in your contacts, to sewing a label into your jacket.
Remember: in person, there is nnever a reason for someone to know/see the CVV number. And anyone who comments on it's absence is worthy of investigaton.