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
It wasn't an assumption. We had this discussion in 'early' (early for me) Shoddybattle when I was saying that Smeargle should be unable to learn Judgment because it's impossible to fight an Arceus to Sketch it. Then we got into a discussion of whether it's possible to Metronome Judgment (it is). Someone then claimed that you could Sketch Judgment that way. This is the source of my error.
Anyway, I'm going to edit the OP and stick this.
Gray areas / points of clarification:
Use of the Transform glitch is almost certainly banned (only possible in early Japanese DP, short version is that any Pokemon that can Transform by any means can learn any Sketchable move)
When they say your team must consist of 4 Pokemon, do they mean that like JAA was (bring 6, see their team, select 4) or you have to just put 4 Pokemon in your team?
Smeargle apparently cannot use Seed Flare or Judgment. Dark Void is legal.
All event moves are allowed.