One of the above moves learned by Pokemon is Metronome. With Metronome you can Sketch any move (but Chatter or Struggle).
Sketching Metronome causes Smeargle to learn Metronome. I just tested it. The upshot is that Smeargle can't have Seed Flare or Judgment in this tournament.
I'm surprised, Obi! I didn't expect this kind of assumption from you. ;P
You can't abuse OHKO moves in a Double Battle without using Gravity.
The accuracy of OHKO moves actually isn't affected by accuracy or evasion changes of any sort. This includes Gravity. I found that out right after training the two members of my own Doubles Gravity team that have OHKO moves. :( They've since been retired.
I think the extent to which they claim to be checking hacks is pretty hilarious, considering GTS. Most of the players could be disqualified right off the bat without even knowing they had hacked Pokémon!
I don't know why you're all so upset about L.50. Yeah, Wireless play should have level scaling. The programmers dropped the ball there. Nintendo seems to use L.50 for most of their events these days, though. It shouldn't really be a surprise.
As has been stated, Regigias is banned due to level, not power. As a side note, however, Slow Start is a far less crippling ability than Truant in Doubles, so it's understandable that Regigigas would be banned and Slaking would not.
If any of you are invited to one of the qualifiers and you want advice on Double Battles, PM me. Don't worry about conflicts of interest; I think I'm going to sit this tournament out. The combination of travel time and no Sleep Clause is a deal breaker. Dark Void Smeargle is going to be ridiculously overused. Idiotic tournament designers...
Also, this is amusing: "Players who are found to be intentionally delaying the pace of their match will be disqualified from the event." No stall teams, I guess. They clearly want these matches to finish in a hurry.