If you believe the box trick doesn't work, try it yourself. Catch a random high level pokemon, give it a power item, fight a few wild pokemon, and deposit it in a box. Its stats will jump up.
I've never seen anyone catch a stantler with a dive ball. That doesn't mean I need video evidence to prove that doing so isn't a rumor!AT THE VERY LEAST, the Smogon DPP EVing Manual should post a caveat that NO video has ever been posted to prove the "box trick" works in Diamond, Pearl, and Platinum (4th generation games). And that until proof is posted, the "box trick" is unverified in Diamond, Pearl, & Platinum.