Fixed that for you.So yeah, illegal combinations are allowed (undoubtedly because they're too lazy to implement the illegal combos)
I too have battled a player using BellyJet, it reminded me of how long I spent searching for a way to breed those moves legally last gen, before realizing it was impossible. When playing against an illegal nature or move combination like that (or modest Eruptran), it's the only situation where I would D/C (despite how rampant that problem is, even in "Free" mode).
Anyone else see a lot of gimmick Pokemon in random battles? I've seen everything from Choice Scarfed Final Gambit Basculin, to Lv1 Sturdy-abusing Aron, to Double-Teaming OHKO machines.