Regarding Samurott, it's still not online under "POKEMON503" (POKE-MON5-0300-0000). It simply says, "The gift is not there". Perhaps they are waiting to send out a Trainer Club newsletter to announce it?
As soon as Wobbuffet leaves battle, the trapped opponent can leave on the next turn. While it gives you a free hit, it can be rendered moot by putting in something that is not often hurt easily by your chosen Pokémon. The only way to make your switch useful is with a move like Giga Impact (I put Gallade in against Mega Metagross and used Destiny Bond to win the battle), but even that is countered by a Ghost type. If you don't KO the opponent, the encore can end, I think, while the Pokémon is away. Pursuit, however, will catch a non-Psychic on the way out.