Reinz:
You are right, as always, in noting that the tac folder is a comforting substitute when it is forbidden to carry a firearm. The rules of this cruise my wife cajoled me into taking, however, forbade passengers to carry any so-called "weapons." As a result, this time I took a page out of DDGator's book and included in my luggage a small 3-1/2" tac flashlight with a strike bezel. It wasn't much, but it was something to have in the pocket when walking around island ports of call.
I had always said that the only cruise boats I would consider would be chartered bareboat sloops of which I would be the captain, and I have preferred to sail out of Red Hook Bay in St. Thomas, U. S. V. I., in the past. In such situations, although handguns are forbidden in the V.I., 12-guage flare guns and phospherous flares are available at any boating supply shop. Those things can serve as fine tools for repelling any unwanted "boarders."
All in all, I found the "commercial cruise experience" to be much like being herded around like cattle. However, the ladies and teens enjoyed it, so I tried to keep a smile on my face and "went along to get along."