Dean, that was a good post. once in a while I do a docking class here in SD and I'll do senarios like you did with the water bottle. You probably remember the customs dock at the south end of SI. if you do you'll know that half that dock is taken by off duty harbor patrol boats, add in a 80' boat clearing in and there's not much space left.
What I would do is take students over to the dock ( on a not so busy day )and I would use whatever was avalable to mark limits ( boarding steps, Trash can or whatever) I would tell them that this step is a 3 million dollar boat, that trash can was a 7 million dollar boat and we have no insurance, now dock.
It was a fun drill, everyone has a good time and by the end of the 4hrs they were docking a C-32 in a 36+/- foot space, granted in the beginning we did around 60 million in imaginary damage.