We should also get some kind of stub to prove we handed bags to people on the pier. I know I would never hand over luggage to the airline without some kind of confirmation in my hand...so why are we so trusting by just dumping our luggage at the pier?
HELLO!!!! When my friend dropped us off at the pier in Miami there was a man who said he'd take our luggage and if we'd like to tip him to do so now. We said okay and started to walk away so he reiterated the tipping part. I was like, good grief, and started to get some money when he said if you don't want to tip don't. So we left, but we were very worried about our luggage and hoped it would make it on. When we got inside I checked with someone to make sure that we left our luggage in the right place. You are right that the cruise line should give guests a ticket to verify how many pieces they have.
In Baltimore we put our luggage in a bin to be loaded on the ship. No one asked for a tip or gave a receipt.