What is the burden of establishing that a purchaser had prior notice of another purchaser's claim, right, or equity?

"The burden of establishing that a purchaser had prior notice of another's claim, right, or equity, rests upon the one who asserts such prior notice." Glaser v. Holdorf, 56 Wash.2d 204, 209, 352 P.2d 212, 215 (1960) (citations omitted). In Miebach, the court noted that because the plaintiff was an experienced businessman and the debtors still had possession of the property, making continuous improvements on it, the plaintiff was on at least inquiry notice of their claim to the property. Id. 685 P.2d at 1077-78.