I read in the newspaper a story about a restaurant that use fake wasp nest to keep those insects away from people (who eat outside)

I never heard about it and I'm curious to know if some of you know about it, if that really works ?

Would be nice to have it when I eat outside at my parents house.

http://www.waspinator.co.uk/faq.html

The wasps bothering you will be out hunting for food, not for a place to stay.
EDIT: I stand corrected - thanks for the Waspinator link

Half a slice of cured ham on a plate a few feet away from your table should keep them busy and away from you. While they don't mind sweet stuff, the do love ham.

I never knew that, thanks Adrian. As far as I know wasps never re-use nests so if you find one, I suppose it is worth keeping to scare the others away.

Neither did I until I typed "fake wasp nest deterrent" into google just to look smug here on EF

Fake wasps nests, and knowing that wasps like ham.

I did not anticipate learning something like this today when I woke up, I'll be honest.