Does a refusal to sign a written waiver of his Fifth Amendment rights barred him from further interrogation under Miranda?

2 Appellant, relying on People v. Fioritto, 68 Cal.2d 714, 68 Cal.Rptr. 817, 441 P.2d 625 (1968), contends that his refusal to sign a written waiver should have barred further interrogation under Miranda. However, it is not clear from the record that appellant's refusal was directed to a waiver of his Fifth Amendment rights or to a simple written acknowledgment of his understanding of them. According to the testimony of the agent appellant was orally advised of his rights as enunciated in Miranda. He was asked if he understood his rights. He stated that he did. He was asked to read a written statement of his rights. He was then asked if he wished to sign the written statement for the purpose of indicating his understanding. "He said that he understood his rights but he did not wish to sign any forms whatever." Further, the testimony of the government agent, while far from clear, suggests that the confession was not the product of interrogation but was voluntarily initiated by the appellant. Had the problem now presented been raised at trial by a proper objection, these ambiguities could well have been resolved.