I model SP, and I have seen many pics, and videos with cabooses on them. To me, just as strange as it would be to see SP with out a tunnel Motor, or a SD45, the same holds for a Caboose. Plus, I could see a practical use for them. In the event that the Road Crew has to manually switch a switch or two from point A to point B, a Switch man could get out of the cab of the lead Locomotive, throw the switch, get back on the train. The Train runs through, then stops, and the guy in the caboose would get out, close the switch, hop on the caboose, and they would be on their merry way, especially in Yards, and junctions.
Also I figure, I'll use Cabooses on Locals, Manifest, and most heavy mixed freights, and use freds on fast Express trains, Z trains and any thing that moves fast.