Wheel locks go a long way towards preventing theft, but they do not come with an absolute theft-proof guarantee. In general, they are labeled as theft deterrents. This means that they are meant to make a theft much less likely.
That’s not to say that they are not effective, however. Having one lug nut that requires a special tool to remove makes it much more difficult to remove any given wheel. Not only does it take different tools to remove, but it also takes more time, which is of the essence when it comes to getting away with stolen goods.
Perhaps the greatest benefit of having wheel locks on your car is that they go a long way towards preventing a theft from even being attempted. Since many thefts are crimes of opportunity or convenience, many thieves will see the lock, then move on to a different car.