Top percentage Pokémon gets assassinated

[DontTalkDT]

Youngster Joey vs Kecleon
Speed Equal
Battle takes place on Mt. Silver
SBA otherwise

Can the stealthy Kecleon assassin take out Joey's Pokémon or does it get caught?

 

[Imaginym]

In the Pokemon games, the DVs/IVs (Basically the genetics/growth rates for a Pokemon's stats that are generated for every individual Pokemon.) are based on the Trainer Class.

Is it valid to take into account what kind of statistics the different trainer classes are grouped into, or do we defer to his claim that it's "in the top percentage"?