Absolutely. While there is no accurate measurement of how much the world’s PPC ad purchasers are wasting on fraudulently clicked advertisements (the search engines won’t share that information as it would hurt their business), people are out there, clicking your ads on purpose, with no intention to buy your products or services. Competitors may try to make your costs so high that you stop advertising (thus leaving more room for themselves), while others, as bad as it sounds, just spend time each day clicking PPC ads because they want to cause you harm. This could be a disgruntled employee, or just a random teenage without any association to your business, but with too much time on his hands and a penchant for causing trouble.
Related Topic: WHAT IS CLICK FRAUD IN GOOGLE ADSENSE ?