Can a competitor sabotage a ranking using the evil sandbox filter of google?

\
This is a very good question. Having discussed all these information, if we don't address this issue people will back fire us. Our research was focused on this issue too. We included some older domains in the test and we successfully found that a competitor CANNOT sabotage an existing ranking of a site through these link filter algorithms. But why can't a competitor sabotage ranking?

Here I explain from the conclusion of our experiment:

What happens with Google is they want the site to be trusted before the site starts ranking very well. So in order to rank well a site should show the trust it has with Google's algorithm. But this trust is a onetime process. If the site establishes its trust with google and starts ranking well then they don't have to prove it again as long as the trusted links exist.

For example if a site is new and the site starts off with good trusted links, then the site doesn't get sandboxed at all. It will start ranking very well, say for a month and an aggressive competitor who has been watching this plans to destroy the ranking of the good site. He spams all blogs, message boards, guest books, posts sitewide links on many sites etc. So will he succeed in sabotaging the ranking of the good site? No, since the good site has already established trust with google algorithm all these links from bad pages will only boost the ranking of the good site. No way will it harm the good site. Google algorithm knows this very well.

So why cant a competitor do this when the site is still new and not ranking?
It is because he won't be aware that a site like that is growing strong, firstly. Unless a new site ranks well for targeted phrases the site is not a problem to any one's eyes. Only if the site ranks will it itch the eyes of evil SEO companies and competitors. Only then they will plan to kill the rankings. But, by that time it will be too late, since the site has already established a trust with google'algorithm based on quality backlinks which it possesses already. So if a site owner thinks of sabotaging the existing ranking of a site by sending bad spam backlinks to their site, then they should remember that they are just actually helping someone rank better than ever. This is one reason why Google always preaches that no one can harm a site's ranking other than the people responsible for the site.

So what is the proof for the above statement?

Our experiment is proof, though we are an ethical SEO company we know places where the bad backlinks are. We sent thousands of those backlinks to sites we monitor which are ranking currently well. We kept those links alive for 2 or 3 months and we were able to conclude that those bad links are doing nothing harmful to the site, In fact it was boosting those sites rankings and google's algorithm never cared of those backlinks.

We are not discussing canonical issues, 302 hijacking, 301 problems etc here, we are just addressing whether a competitor can sabotage ranking for a site through link spam. There had been cases where 302 hijacking by external domains hurt a site. Matt cutt's (Google's senior Engineer) blog is a proof for this. Dark SEO team hijacked Matt Cutts's blog through a tricky 302 redirect, but that is a different issue and this article deals with sandbox filter only.