Why are people still insisting on estimating traffic of other people's sites? Here is a tip: Alexa is rubbish, i.e. wrong. At best, it is a very disturbed refle

Why are people still insisting on estimating traffic of other people's sites? Here is a tip: Alexa is rubbish, i.e. wrong. At best, it is a very disturbed reflection of reality. Also, why does it say "Don't refresh or quit the page until the end of the report generation..." near the top? What happens if I stop half-way through because I didn't see this warning?