Snow chains

My wife is about to take delivery of a new company car - a Skoda Superb with 18" wheels. The users handbook says that snow chains cannot be used with this wheel. How do other owners cope? Is the problem clearance behind the wheel or on the wheel arch? Do we have to buy those expensive devices that clip on over the outside of the wheel only using the wheel nuts or do we have to buy another set of wheels.

I cannot beleive that Skoda have not thought this through and sell a car that you cannot fit snow chains on. After all they are a legal requirement in many places.