If an employer is so disorganized that this doesn't become obvious during the first month of working there, they probably have much greater problems than cheating on their idiotic cargo cult coding tests, and fixing the cheating would do absolutely nothing to save the company.
You have no idea how deep the rot is. Here is a classic scenario I know of. Large ships have plenty of space for rats to hide.
Large American Inc. is a large company we all know off and which is always somewhere on the front page for some news. Mr X is a manager there how arrived from India on H1B and now perhaps has a green card.
Mr. X brings his younger brother Mr. Y on F1 visa. Mr. Y then joins a consultancy. Consultancy claims Mr. Y has 8 years of experience, knew AngularJS before it was invented (true story) etc. and submits it to Large American Inc. for a project that Mr. X is spearheading.
The consultancy then send a proxy for phone screen and real interviews. The consultancy, Mr. X and Mr. Y all pull a lot of strings here. favours are exchanged.
Mr. Y then joins Large American Inc. as a consultant with a salary of $120K under Mr. X.
Mr. X and Mr. Y conceal the fact that they are closely related.
In many cases consultancy hires another person in India whose job is to give 24x7 phone support whenever Mr. Y has to do his work. Screenshare etc.
"this doesn't become obvious during the first month of working there"
This is a gross oversimplification of the problem. Do you know how difficult it is to fire a person? Do you know how much it costs to hire someone? You've given this person a relocation bonus, possibly put in the work to set up a visa, given the first chunk of a signing bonus....
I'm so tired of the assertion that it's "difficult" to fire someone, even insofar as "difficult" means "HR won't allow it." HR's reasons are stupid, particularly if you're in a so-called "right to work" state. I work on multi-million dollar lawsuits for a living, and in every single employment suit I've worked on involving an individual who was fired from a large organization, that person had already been through some kind of PIP.
When talking about employment law, "the right to work states" is often used as a generic category used to refer to states with weak employee protections, since the right to work states generally are also red states: https://en.wikipedia.org/wiki/File:Right_to_Work_states.svg
Can you find an example of where "right to work" is used as a generic category instead of its actual meaning:
"Right-to-work laws are statutes in a reported 26 states in the United States that are an effort to give employees the right to work without being required or compelled to join to a union."
It does. I'm talking about the fact that the fictional employee we're talking about is most likely non-union in a right to work state, thereby making it easier to fire them (without union intervention).
Why would you cheat, though? You're going to get the job and probably be completely incapable of doing the work. Not to mention there's usually an in-person tech interview afterward.
I know some people in bay area who are making > $100k in cash (no taxes paid) just by answering screening interviews on other people's behalf.
This is called "interview by proxy" and the person generally takes first month's salary as remuneration in cash.