We have been taking our own bottles of wine onto ship for years and paid corkage on any bottles over the first two (1 pp)
In the past our extra bottles had a label put on them to show we had paid corkage and we carried them on. Earlier this year we took 12 bottles on our Transatlantic from Miami - they checked in the bottles near check in and they were delivered to our room and corkage charged to our account - no labels at all. Everyone knew corkage had been paid. We took bottles to the dining room, specialty restaurants and even pool bar when we were watching a movie. No distinction between our two free bottles and corkage bottles. They can be drunk anywhere. It's a little awkward to have a dozen bottles along with suitcase and hand baggage, but well worth it if you have nice wines, since a $5 supermarket bottle is $30 on ship. We have also bought bottles of wine while in a foreign port for the day and had that charged to our account as we got on board. Never been a problem, never taken away until end of cruise.