What is the legal test for making a request for admission?

"Although requests for admissions are included in the Code of Civil Procedure among discovery procedures [citation], they 'differ fundamentally from other forms of discovery. Rather than seeking to uncover information, they seek to eliminate the need for proof.' " (Murillo v. Superior Court (2006) 143 Cal.App.4th 730, 735-736.) If a party does not serve a timely response to requests for admission, the party who propounded the requests "may move for an order that the genuineness of any documents and the truth of any matters specified in the requests be deemed admitted, as well as for a monetary sanction . . . ." ( 2033.280, subd. (b).) "[T]he burden is on the propounding party to file a motion under [section 2033.280, subdivision (b)] to have requests deemed admitted." (Appleton v. Superior Court, (1998) 206 Cal.App.3d 632, 635.)