Yes, that would be fine. I know once we arrive at the port we can re-lock the luggage, but just never have. This next cruise we are staying a day prior at a hotel, so I may go ahead and lock them and see how that goes, but you should be fine. You're right its the airlines that require us to leave them un-locked in case they have to do a search of a bag or 2, so far mine have been fine, but you just never know??
You'd be a lot more secure if you buy a package of cable ties from your local K-Mart or hardware store. You carry a nail clipper to remove them and they won't cost you anything if security decides to remove them and check your luggage. If security decides to check your luggage and you're not around, they'll cut through the padlocks.
Oh what to do about those locks! Starting out in Omaha - no locks allowed & they opened each & every person's luggage & you could give them your lock & they would put it on for you but you were not allowed to touch your luggage again. Then in FLL they said - yes put the locks on them. So you never know what to do. We don't use the locks that you use a stupid key anymore - we use the little combo locks-easier & quicker but still keep the zippers shut.