On cruise ships, the CAMERAS are not invasive and unless you are in the know, you will probably never see a security camera, except probably at the embarkation disembarkation area.
Then, the SECURITY STAFF are generally dressed in the same uniform as officers or they are in plain clothes and tend to be quite reserved and on the down low. Ocassionally, they may carry a radio or some other communication device. If you do not know who they are, it would never cross your mind that they were anyone other than officers or other passengers. I only know because I am very security conscious and am often up and around at those times of the early morning when everyone up knows everyone else who is still up at that time, and you guys are all friends anyway; and anyone not in that clique requires scrutiny.
In any event though, if you really want to know who the security people are, by all means....do something stupid like get real drunk and start a fight, or try to bring drugs/weapons on the ship or slap an officer or go up on stage in the middle of one of the shows and try to moon the audience. Any of those activities should guarantee a personal meeting with them. (NOTE: I have not personally tried any of those stunts myself, although one security guy on my last cruise was so tall and buff and cute and HOT..........
!!!!! just joking..).
Having said this....