d, 848 F.2d 1009, 1011 (9th Cir.1988) (same). We recognize, however, that not all courts have adopted this standard. See, e.g., United Slates v. Gonzalez-Sanchez, 825 F.2d 572, 578 (1st Cir.1987) (holding that government bears the burden of demon- strating by adequate evidence that there has been a substant