What is the burden of proving a search or seizure without a warrant?

Defendant also claims the court erred by imposing on him the burden of showing the search was arbitrary or harassing. The court did not err. "[O]nce the prosecution has offered a justification for a warrantless search or seizure, defendants must present any arguments as to why that justification is inadequate. [Citation.] Otherwise, defendants would not meet their burden under section 1538.5 of specifying why the search or seizure without a warrant was 'unreasonable.' This specificity requirement does not place the burden of proof on defendants. [Citation.] As noted, the burden of raising an issue is distinct from the burden of proof. The prosecution retains the burden of proving that the warrantless search or seizure was reasonable under the circumstances." (People v. Williams (1999) 20 Cal.4th 119, 130, 83 Cal.Rptr.2d 275, 973 P.2d 52.)