I personally don't mind it, the first time I saw it happen I couldn't stop laughing although it has never been done to me.
I don't think it is often competitively someone uses 'FEAR' but there are a few ways to prevent it, such as entry hazards, forcing the sash Pokémon into battle which can happen, those Ghost type Pokémon.
This is only my opinion of course, if it was me it happened to the first time I saw it and not a friend, I would have probably needed to replace my DS :)