Based on what I've read on here and on a Fort Facebook group I've joined, I'm inclined to think that property theft is something to consider when preparing for a trip to the Fort.
TeamBradford and family had their door jimmied while they were in the parks. I don't think anything was stolen, and they suspect their loyal dog scared them off, but I'm sure the incident violated their sense of security nonetheless.
There have been several instances of bikes driving themselves away.
I suspect the permeable nature of the Fort, in addition to its size, contributes to it.
We tend to camp in state parks in our home state (TX), and our state parks have park rangers that are very active, involved, and are licensed law enforcement. They patrol at night, and in many parks the gates are locked after a certain time. In addition, a person has to check in, pay (unless they are a parks pass holder), and keep a parking pass in the window. They check license plate numbers as you check in. In other words, you aren't hanging out at the park without their knowledge. Even with all this, we lock bikes when we are leaving for the day. We also hide our nice cooler since we've been told that the RTIC/Yeti type coolers are sometimes stolen in Texas campgrounds during the summer.
We do leave our camp chairs out unless we are expecting rains and/or winds.
We've never had anything stolen, but we also haven't been camping long. I realize that if they want it they will take it; however, we will do what we can not to be the low-hanging fruit.