Desktops have been having this issue for years. If it's a concern use a surge protector with battery backup, same as you would for a desktop.
A simple question- if the laptop switches off in an improper way while downloading stuff ( e.g. when it is suddenly switched off while running directly on AC power ), does this harm the hard drive in a serious way?
I ask this because i have not been using the laptop battery at times. However, due to one reason or the other, the electricity supply has got cut many times when large files (movies etc) are being downloaded.
though i have not observed any problems with the downloaded data, i am equally worried about my hardware !