Links from deindexed sites - how serious?

Hi everyone

I have bought small numbers of posts on blog networks in the past, even though I read people's warnings on possible consequences. The effectiveness of the technique makes it hard to resist. I am currently working on building my own network which I will keep secret and only use to promote my own sites. However, I am curious as to just how serious it is when a blog network gets deindexed and you still have links back to your money site on there?

I have used the search function and read most of the threads I could find about blog networks. There are plenty of people saying how risky they are but I can't find a report of exactly how bad the consequences are.

So for example, lets say for your money site you have a 10 year old domain name and a reasonably white hat back link profile with say 200 referring domains showing in majestic seo. You then buy 50 posts on a blog network for this site. The blog network then gets deindexed by Google. What would you expect to happen to your money site? A decrease in rankings? A penalty of some kind? Your money site gets deindexed even?

Can someone with direct experience of this tell me how bad it actually would be?

thanks