Regardless of if being right or wrong a couple of cruises ago we went to our cat.11 cabin on Lido deck right after boarding. We went thru "open" doors (they were closed when we came back out...) to our cabin and dropped off carry-on with medicine/papers/etc. Put passports/money/etc in safe and locked it. Met our steward, donated $20 to the cause. We returned about 2ish and all was well. We were one of the first ones on with VIP embarkation (other than wedding groups) so I guess they had not shut the doors yet.