My understanding is that while it is always a good idea to remain on good terms with marina management many of these organizations are far more interested in collecting rent than providing protection. Many marinas have no practical physical security present. If it has gates they are often disabled, broken, easily bypassed and seldom is there anyone watching. Often a thief just has to follow someone in. I have never seen one with any security on the water side.

Getting friendly with any live-aboard occupants in the marina are IMHO far more likely to get end up seeing concerned and watchful eyes on your boat. Marina managers are often just doing a minimum job. Live-aboard sailors have a much more vested interest in keeping thieves away. They are not only looking out for your sailboat. They are looking out for their home. A higher level of motivation.

They are also often the main, sometimes the only, protection if any alarm goes off while your away. In large marinas where the vast majority are once-a-month weekenders an alarm can sound until the battery dies before anyone bothers to see what the commotion is about. Boat owners can easily show up and find their dock lines, still tied to the boat, leading underwater.

Live-aboard sailors can be busybodies but they are also the ones who retie lines that have come loose, ask suspicious people what they are doing and who will act when your bilge alarm sounds at 2AM. Many marina owners actively exclude live-aboard sailors because they are 'high maintenance'. Sad because they can also be the heart of a community in a marina.