He doesn't have to put it to the test. Hundreds of other people have done that for him. There have been hundreds, if not thousands of Bitcoin thefts over the years, amounting to millions of dollars worth of coins.
Prosecutions - 0.
Criminal charges brought - 0.
Arrests - 0.
I'd say the hypothesis was pretty well tested.
Also, I have no idea why you wish to claim with absolute certainty that Bitcoin theft would be regarded as a criminal offense by every court in the world, despite a lack of evidence for that point. You seem very passionate about this issue, to the point of being quite rude to those who disagree with you. Your passion makes me wonder if your conviction is based more on a kind of "Bitcoin zeal" rather than an intellectual conclusion that you have reached. The fact you make grandiose claims based on your assumptions (such as "Bitcoin theft would be recognized as theft by any country with a functioning legal system") makes me further question the rigor of your thought processes. Also, please forgive me if this sounds rude, but I've noticed you have problems with comprehension and a lack of critical faculties.
There are a few people on this forum who are so enamored with Bitcoin that they refuse to acknowledge has any shortcomings whatsoever, and they become irate when confronted with evidence to the contrary. From reading your post in this thread I believe you fall into this category, so there's not really much point in engaging with you. It would be like asking the Pope to consider the merits of open minded Agnosticism.