That's a textbook example of the fallacy of anecdotal evidence. My house has never been broken in to, ..... Yea, until it happens to you.
You are correct, what I suggested gathering is indeed anecdotal data. The premise of this thread has been the need to protect valuables from theft and fire; a reasonable concern? Yes. A concern supported by data? I'm not so certain, at least for sailors.
Because I'm a data based guy, I went searching for data on marine theft, specifically I went searching for data on marine theft that could be thwarted by installing a safe, i.e., the theft of money, jewelry, and other small valuables. I couldn't find any data. That doesn't mean that it isn't happening, it simply means that it is not happening with sufficient regularity or of sufficient value to warrant anyone keeping track of it.
What kind of theft data is recorded? It appears that boat theft is the only data being regularly compiled. The National Insurance Crime Bureau publishes a Watercraft Theft and Recovery Report. (
2016 Watercraft Report | nicb.org) In 2016 only 66 sailboats were stolen as compared to 1,167 personal watercraft. The thieves just aren't interested in our sailboats (the report doesn't distinguish between a small trailerable sailboat and a larger boat).
Based on what I read, there is concern if you have a trailerable power boat, an outboard, fishing equipment and electronics that are in the cockpit. As the NICB report shows, there are stark regional differences. Florida and California rank high on the list of stolen boats (and presumably equipment) while states like North Dakota rank pretty low.
The consensus among the various articles on the topic is that thieves are lazy, they want easy targets with high value that are not easily traceable. There was some speculation that powerboat thefts were really outboard thefts, the thieves remove the outboards and trash the boat. Fishing equipment and easily removed electronics are also high value targets.
While there may be local exceptions, protecting small valuables just doesn't seem to be a big problem. I don't think thieves expect to find large bundles of cash on a boat. The risk-reward ratio just isn't good enough to take the chance. But, swiping a boat on an unlocked trailer? That's quick and clean.
I bring all this up, not to start some raging flame war or to troll the forum, but rather we humans tend to be poor judges of risk. We tend to worry more about low probability events than high probability events. We let our emotions over rule reasoned judgement. There is lots of information, backed by good research, that describes common fallacies in our judgement. A couple of notions to start with are the Confirmation Bias and the Conjunction Fallacy, google the terms or look them up in Wikipedia.
As Mark Twain is reputed to have said, "It is not what you don't know that gets you into trouble, it is what you know for sure that just ain't so."