On Carnival to Alaska, they took our luggage directly from the plane and we didn't see it until we got into our cabin. On the return, they took it directly to a staging/holding area in the airport and you just walked in and tried to find it.
We never had to tip the baggage people, because we never saw them!
A lot of people do roll-on some suitcases (oh and of course a tote). I just don't like to hassle with hauling stuff around.
I tip $2 a bag, because it's a feeding frenzy sometimes to get a porter in LA. I've also found that if I have the money in my hand and visible, the porters are always happy to grab my bags right away. :-)