The credit bureaus don't like doing their job and investigating items on your credit report if you don't have to. It has been my experience that disputing inquiries to the credit bureaus will accomplish nothing and the credit bureaus will mark that dispute as frivolous or ignore it. They might be nice and send you a letter stating they don't investigate inquires, why, I don't know. Might want to note that inquiry disputes don't work with credit bureaus.
Some creditors will ding your credit report multiple times when you only authorized them to do it once. That is why you can't dispute to them. It is always good practice when feeling out paperwork to make sure your credit report won't be getting pulled unless it is absolutely necessary.
