Outline around "Selection From Path"

[rich2005]

Anti-aliasing are semi-transparent border pixels. I should not have really used that term here but you get these that show up as a faint line after a copy or cut. 

I did see the faint line but I could not reproduce it, so I have to ask

Do these only show in Gimp but not in an exported jpeg or png ?
Is the line moving, aka crawing-ants ?
Does the line go away using Select -> None