Royal Caribbean has perhaps the most dysfunctional website management of any major cruise line. It is a constant crisis with their posted policies. Just look at their disaster with the price guarantee change. I don't understand why this is so difficult for them.
As to their beverage policy....I swear, less than a month ago they had updated it to cover ALL personal beverages - booze of course, but also soda and water. It said nothing was allowed. I just looked at it not 5 minutes ago and now it is back to the dire warnings about personal alcohol only.
As was mentioned previously, a reasonable amount of personal sodas or water should be fine. I define that as a 12 pack per person, which is also what Carnival recently set as their definition. I'd like to think Royal looks at it the same way.