I've never had a bike stolen on tour, but I had a camera stolen in the French Alps in 2016, along with some sweat cycling clothes that I'd worn that day (WTF???) from a campground in Switzerland. It was a lesson that some people will steal anything.
Generally I make a habit of keeping my wallet, phone and passport on my person at all times and keeping the bike locked up. The one time I didn't apply that habit to my camera it was stolen. Go figure.
__________________
I am clinically insane. I am proud of it.
That is all.