Having a document notarized doesn't mean that fraud won't be an issue. Someone can still write you a bad check or back out of a contract. What would you have notarized? What type of business are you in?
You are correct! Notarization does not prevent fraud, it helps to curb fraud by properly identifiying the signatory. Nothing more. Actually, I have worked for the bank of america for 17 years and run my own small business. Of which has nothting to do with your question.
There is no intrument or process which will stop fraud. However, there are measures which a prudent business owner can take to diminish the risk of fraud. In addition, a notary public has the ability to place the signer under oath which attaches purjury and that becomes a judicial issue with jail time of up to 10 years. Just because you don't understand something, does not mean there are other people who might be able to share positive quality knowledge with you.
However, if you still believe a supieror knowledge base is at play here. Please feel free to site case law, which contradicts what have have shared.