Hotel industry standard is that Bell Services positions are tipped positions and are paid as such - similar to a server who is paid less than minimum wage under the premise that tips will make up the difference, and should be reported as income. This is why most Bell Service staff members are so eager to help you with your luggage when arriving, etc. Because of this, it would be customary to tip any Bell Service staff member that handles your bag - whether that's checking and tagging it, retrieving it, or delivering it to your room. At the hotel I worked in, Bell Services would keep the tips they earned which doubled as incentive to assist as many guests as they could. This is also why its best to tip anyone who handles your bag. There are some hotels though where Bell Services will pool tips and divide them up at the end of each shift, but they should still be tipped when providing service to you - which would be whenever they handle your bags.