@Steve Evans
I was guilty of this acdentley my home wireless had the defult id and open (yes I know I should have changed it but I lived in the middle of noware in scotland anyboady close enought to puck it up had to be sitting on my drive) when I stayed in a flat in didcot my computer auto connected to one with the same iisd and no conectin it was only when my brother msned me I noticed