Yes that is why you have to give your SSN or EIN when you set up your account. Google will report your earnings. If you used fake info. Then no for not till the feds catch up to you.
He is assuming you are using adsense. If you use someone else, then they will report your earnings unless they are located out of the USA. They report it because that is a requirement of employment is to file certain forms and report spending. They have to do it for legal reasons. You can probably get away with not paying taxes on small PPC earings, but I recommend that you just pay it.