Originally Posted by minicivan

You can get another site banned. People argue about this point all the time. It can be done. If the site is new, its quite easy to make it go away for 6 months or so. If its older, established and has a ton of great backlinks, it might not be possible or at best, it will just take a temporary dip i the SERPs depending on how crazy you get with it.

You don't need to buy links. There are plenty of tools and bots are easy to make build links.

If you were "buying" links, it would typically come from well established sites, so it would be very difficult to harm another site like that and the net result would be that you just gave them a bump in the SERPs, not the other way around.