Silicon Valley has a lot of consulting companies and they are, to various degrees, corrupt.  Examples of corrupt behavior include:
a.  Providing carnal benefits to certain employees of the client company to become a preferred vendor.
b.  Lying to the contractor staff regarding their cut.
c.  Falsifying resumes to the extent that one of my friends called me asking if I had worked with a certain person.  This person was being touted by the contracting company as having worked at my company (very big one) on a certain technology (which only 20 people did and all were in my team).  Oops!
d.  Fake certifications, degrees, awards and whatnot.  One person was a high school graduate and claimed to have a BS and an MS from a certain country.  Later on I found out that that was his basis for getting an H-1B visa!
e.  Fake home address in Florida to escape California state income taxes.
f.  Padding - Work 20 hours, report 30.  Usually happens in collusion with client employee(s).
g.  Phone screens handled by someone other than the candidate.  I once did the screen and after the technical questions, asked him what non-technical books he had read recently.  He mentioned Camus.  I was impressed.  When the guy shows up to work a week later, I told him that I was really impressed.  He said "Who is Camus?"  Oops.  I made sure he could only bill for 2 days before being escorted out.
Andrew Gumperz
During the late 1990's it was common practice for some pre-IPO companies to give stock grants to customers as an incentive to choose their product over that of a competitor. Grants went not just to the company purchasing their software, but also to individuals at those companies who made purchase decisions. I know of a couple individuals whose stock options received as an incentive to choose one company's technology over another eventually had value of $50+ Million. The practice was not technically illegal at that time, although I believe the federal government takes a different view of it today. 

Another common scam was to trade systems and book the revenue as though it was a sale. if I sell a system for $1 million and you sell a different system for $1 million, we could give each other our respective systems and both claim the value of our systems as sales. Some companies used this to vastly inflate the apparent sales of products which no one really wanted.
Arun Kulkarni
I have came across some new type of deals happening in Silicon Valley called as Win & Win situation. Suppose you are part of a sales team of an insurance  company and you are selling this to a Software Company. What happens in this new "Win Win" is you agree with that software company to buy product from them for your company software needs & same they will buy your insurance for their company.

The Silicon Valley Mafia is The Sandhill Road Venture Capital frat boy company bosses in Palo Alto, their National Venture Capital Association (NVCA) partners and the tech companies (Google, Tesla, Facebook, Amazon, Twitter, Linkedin, etc.) they control. They are sometimes referred to as "The Deep State". They have purchased California, New York and Washington, DC politicians (mostly Senators) who they also control.

They hire rogue ex-intelligence agents to operate Fusion GPS, Gawker/Gizmodo, Black Cube, ShareBlue, New America, In-Q-Tel, Podesta Group, Media Matters, etc. massive media attack programs against competitors, reporters and outsiders. They collude on black-lists, valuation controls, election manipulation, search engine rigging, domestic spying for political manipulation, stock rigging, insider trading, executive prostitute clubs, trophy wife assignments, the bribery of politicians and worse. They are felons who pay politicians to halt investigations and interdiction efforts.

They are widely covered in news media articles as: 'sex abusers, cult enthusiasts, elitists, rapists, woman beaters, probiosis abusers, sexual work extortion operators, extremists, arrogant clones of each other, tone deaf, echo-chamber reinforcing, misogynist, racist, manipulative, insecure, covertly gay, corrupt, thieves' and other anti-social revelations. They are not limited to California and also operate out of New York and Washington DC.

They use their monopolistic control of the internet to massively and exclusively scale services that only they control and use to abuse the public's privacy, human rights, invention rights and information. They run their cartel like the old Italian Mafia once did.