I would give the guest your room number so they can tell the guard "I'm here to see Person X in room Y and having dinner with them". Disney doesn't give out room numbers so having that info will let the guard know that you have been in contact with this person they are letting through the gate. Also, let the guest know to have their driver's license out and the guard might take down their license plate number. Any or all of that could happen. Best to be prepared.