They are a worth while investment, and are very difficult to overcome.
If you read the instructions and look in the box properly, you will find little coach bolts that you snap off in the head of a couple of the allen bolts, ensuring no-one can just unbolt the attachment and slap on a wheel from a sierra/ escort etc.
If you need to remove it, you drill it out....hassle??? Not really it's easy to do, and you will have the time/ equipment to do it. Potential theives may not.