that the lime slice in the top of a bottle of Corona is to keep the flies off.
francois,
My wife and I go to Mexico about once per year, Cancun mainly. In doing so the Mexican people always expected us to push the lime in. My wife used to take it out, and a man said, "no, no, push it in" and she did. I think they have just gotten used to our American ways. Either way, Corona without lime just never taste the same to me. I like my lime. :)
Take Care
Dragon