Thieves are a pretty wide gene pool however, with lots of different motivations! And by that rule, you would eliminate most of Australia and New Zealand and especially the Irish in Australia and other former colonies and countries (like the US and Canada), who were regularly deported (or fled in fear of prosecution) for theft and other crimes.... More seriously -- leaving dogs outside alone, especially a small friendly breed with profitable puppies like the cavalier, is simply asking for a catastrophe in many places. In the UK, Ireland and US you regularly see articles about stolen cavaliers. The police here in Ireland have confirmed before that they are one of the most stolen breeds.
I know UK police have said that a microchip is about the ONLY way to confirm ownership and prosecute a theft, so owners, be sure to chip your dogs. Also, neutering pet dogs, and getting tags that clearly state the dog is neutered and chipped also help because then it is clear they are of no use for breeding and can also be tracked. That's my advice to all.