Here where I live in Düsseldorf we have many tubular steel bike stands, known as Sheffield Stands in the UK I believe.
These are often easy to cut silently with a pipe cutter, which is a small manual tool with hardened steel disks that you rotate around a pipe so it gradually cuts a groove through the metal. Thieves here have not only cut and directly removed a bike, but they have cut and reassembled the tube so it looks intact at first glance. When a valuable bike is locked to the prepared stand they just come and pull the joint apart in a matter of seconds. The preparation can be done in the dead of night and the theft is so quick it can be done in broad daylight.
Link (in German to a secondary report as the original is behind a paywall):
https://www.rtl.de/cms/perfide-masche-b ... 16544.html
Running a hardened steel chain through the pipe during installation is one solution. Another is to use solid steel bar instead of tube.