The arm of the law might not catch everything, and when it does work, sometimes it works slowly.
Companies like Uber and AirBnb got ahead by skirting the law, and had to change their products in some European countries (like Spain) because lawmakers eventually saw what they were doing. AirBnb are now required to ask for tax ID, and Uber had add artificial delays in order to fit within the law that existed. But when they initially launched, they didn't do these things, it was only after pressure that they changed.
But that was not the only use of AirBnb, tons of properties were bought and used only for driving what essentially is a hotel in those properties, without registering with the proper entity and paying the appropriate amount of taxes. This was not legal, and never was, as hotels need to have a license, yet AirBnb allowed those entities to continue running on the website until the courts got involved. If that's not skirting the law, I don't know what is.
Now of course, AirBnb requires its users to specify their tax ID before they can let out their places on AirBnb, as the law (already existing since before AirBnb) requires.