Welllllllllll, not necessarily.
With my DH, it was more about it being "official" or "standardized" somehow... like it meant more if someone else were to have administered it or something.
He finally conceded that $30 and the rules governing FLO's process made it official ENOUGH for him to believe it. Grudgingly.
Though he did grumble plenty about whether or not she'd have "done that well" with someone else, and wondered aloud whether it was valid at all, since she didn't take the entire 4 hour battery in "one sitting" (yeah, okay-- this is a guy who hasn't spent a lot of time around other 5-7yo), etc.
But I had him proctor/administer one section-- so he KNOWS that it was real, on some level. That was the section where DD was being completely goofy and deliberately messing with him while she bounced all over the room like a tigger, incidentally... so she missed two on that section, I think-- which was easily her lowest score on the entire battery. LOL.
Anyway. It wasn't so much a trust issue between my DH and I, as much as an external validation, independent data collection issue. Neither one of us is much of a fan of whole-hog unschooling, and we both had some serious concerns about DD's apparent reluctance to do formal learning activities "on-level" during that year of attempted "homeschooling" with her. It was definitely a worry for both of us, and we felt that we needed something to say where she was, in terms of achievement/placement. KWIM?
We'd both have preferred for someone else to have administered it, as well-- but in DD's case, my mother was the only person we'd have trusted DD with (and she, likewise) at that age, so were were a bit stuck. I'd have happily used a family friend or neighbor or something, though. Basically, you just read the script to the child-- it's not hard or technically difficult, but the proctor should be someone that your child knows and is compliant with-- at least reasonably so.