Deadbolt Lock

I'm hoping that forum members who have had a lot of experience with various types of deadbolt locks can give me some suggestions. For years, I've suggested that older seniors (and others) designate one (or more) room(s) in their home for items they want to keep away from others. Initially, people often naively assume that simply having a traditional (exterior type, keyed) deadbolt installed is enough. Sadly, they often quickly discover how incredibly unethical many people are, including people they thought they could trust. I've been trying to think of some type of solution to this problem. Ideally, such a lock would have a high degree of reliability and would allow at least two types of (non-cellphone) access (such as using a physical key or keying in a code). Unfortunately, it seems like many of the types of deadbolt locks that are oriented toward the residential market tend to have bad reviews. Any suggestions?