§ 402. Fraud; notice only by registration. Except in case of fraud and except also as herein otherwise provided, no person taking a transfer of any registered real property or of any estate or interest therein or lien or charge thereon from the registered owner shall be required to inquire into the circumstances under which, or the consideration for which such owner or any previously registered owner had the title registered, nor shall such transferee be affected with notice, actual or constructive, of any unregistered trust, lien, claim, demand or interest whatever; and the knowledge that an unregistered trust, lien, claim, demand or interest is in existence shall not of itself be imputed or treated as fraud.