Only if someone gets his hands on your cookies. If that happens, your computer is compromised anyway and you have more things to worry about.
I always have this strange fear that someone has easy access to my cookies and I obsessively clear them out almost instantaneously and constantly. I never save any log-ins or allow excessive cookies. I do not allow them to sit on my computer for longer than necessary. I might have a paranoid approach, but it seems to be working so far.
This seems like a waste of bandwidth for someone who's last posted almost 2 years ago.
Not that much bandwidth though, and it's not like you can squirrel away your unused bandwidth for future endeavors. Am I wrong?