What does anticipation do other than the Pokemon shuddering?

Question

Do ohko moves or supper effective moves have less accuracy, is the anticipation Pokémon's evasion boosted?

Answer 1

Nope. Anticipation has no effect on the accuracy of the Super Effective Move or OHKO move.
It meerly warns you that the opponent has a OHKO / Supereffective move.
Basically, it's a warning.