"If you are not polling station staffs, you cannot go inside the polling booths unless you are going to cast ballots. Catching Pokemons there is prohibited. Normally, if you are not voting, you are not allowed to get inside a polling booth - not for catching a Pokemon, not for anything." - Election Commissioner Somchai Srisutthiyakorn
The Election Commissioner is actually a fan of the game, but wanted to point out that the polling areas aren't exactly the best place to hunt for Pokémon.