I've had a bike chained - annoying as it was parked along with dozens of others on a "No parking couples days" and picked at random. A sign that was later pointed out to me by a local was tiny, mounted high up a pole and, at the time, I had no idea what a "couples day" was.
I've never seen a Wave or a Scoopy chained, always a more upmarket scooter, as ridden by tourists - the bike in this story is a brand new (red plate) ADV160 and so pretty much guaranteed to be ridden by a farang victim.