Is a probation condition that allows a probationer to be searched "with or without a warrant and with or without probable cause" valid?

In United States v. Jeffers, 573 F.2d 1074 (9th Cir.1978), we held that a probation condition which provided for warrantless searches by a probation officer "at any time of the day or night," "with or without a warrant and with or without probable cause" was overly broad and not in keeping with the purposes of the federal probation statutes. Nevertheless, we upheld the search in that case because there was "reason to believe" that the probationer was violating his probation, and the search was made at a reasonable time and in a reasonable manner. 573 F.2d at 1075.