Can Alexa and Compete traffic stats be faked? How to verify stats before buying a site?

We all know that Google Analytics stats can easily be faked with bots and proxy servers. Which makes objectively finding good sites to buy Flippa very tough.

But what about Compete.com and Alexa rankings? Can those be faked as well?

What steps do malicious sites take to fake their rankings and how can the falsified stats be spotted?

If there is a value / money to be made associated with inflating rankings, then there is the possibility. Googling shows a bunch of approaches used to increase Alexa ratings, but typically these known approaches are discovered and users penalized. Its too much of a cat/mouse game to detail here - since the approaches and callouts change rapidly.

Suggest your search a reputable source - SEOMOZ (now moz) is good - to keep abreast of recent SEO efforts.