I have never seen or heard of this being done. The water on board is at least as safe as at home. And their utensils are cleaned and sanitized very well. You are far more likely to pick up a bug from handrails or grocery shopping in your own town. Just wash your hands routinely on board the ship. Regular soap is fine, but wash long enough to sing Happy Birthday under your breath. No, the soap isn't aging, it's just an easy way to time it. The hand sanitizers are a good addition, but even they won't kill viruses the way old fashioned hand washing does.
I did a thread a while ago where some people do not trust the water on ships, even the stuff you boil in a kettle....crazy I thought! You stand MUCH more chance of catching something from a handrail....wash wash wash!
Some answer questions...I also question answers
actually i would think that the utensils brought from home would have more germs on them then the ones you get on the ship, think about that can you sanitize them in your cabin after you use them? I think that the information you got might refer to the islands, and yes avoiding ice cubes and tap water is probably not a bad idea if you get something from a local vendor