Check noonsite. They note some minor thefts having occurred at Sutera for boats at the south pontoons, and, if I remember correctly, some when folks anchoring
in the general vicinity as well. Don't remember how recent the reports are.
Also, the advice given above on reservations seems sound as noonsite posts note that the club is "member oriented" and that space for visitors is limited and should be booked months in advance, if possible.
By the way, I spent about a decade "sailing" with the Navy
myself, and I may be in KK around late March. Shoot me a PM on your itinerary when your plans are clear, and, if our schedules coincide, maybe we can meet at Sutera for a beer
Best of luck,