What are the possible penalties of breaking a no compete clause by taking a job in the same field with a different company?

It varies from state to state.


Also it depends on your job duties where you were working and where you are going to work.

How are they going to know you're working at a competitor?

I don't remember the Supreme Court cases right now and I don't have access to them.  But, it comes down to that they are not enforceable.  A company can't keep you from making a living.  The company can keep you from receiving benefits such as employee matching savings plans.  Many professional type jobs (ie Doctor) will match and add to your retirement account, that money can be pulled, and for some it is quite a sum of money.

D

Most courts take a very dim view of restrictive non-compete clauses.

You cannot be prohibited from earning a living in your career field.

Do you live in a "Right to Work" state?  As posted earlier - your rights vary from state to state.  If you think you have reason to be concerned you should consult an attorney that specializes in employment law.

CWO

In many states, they are enforceable, subject to limits of reasonableness. "Reasonableness" generally means that the agreement cannot act as an absolute bar to earning a living. Geographical and temporal restrictions are generally enforceable, provided that they are related to the beneficiary's (employer's) operations. A statewide ban on competition will generally not be enforced if the employer draws 90% of its business from a single county. However, a countywide ban will probably be upheld. Anti-poaching provisions (prohibiting contact with the employer's customers) will generally be enforced.

Don't let anybody persuade you to casually disregard such an agreement, unless it's a lawyer in the jurisdiction where you want to work. You will end up well and truly screwed if your sea lawyers inadvertently mislead you. It is certainly worth 2 or 3 hundred bucks to know for sure what you can and can't do, since the penalty for violation will likely include disgorgement of all profits gained through a violation.

Non-competes are virtually worthless unless specifically tied to additional compensation and a very short time limit.  (IE, they pay you your salary for another 6 months after quitting and you aren't allowed to work for anybody during that time).

Most cases get tossed out.  The only real usage of these is if you were to quit company A, go to company B, and share everything you know about how company A does things.

Even then most cases get tossed out.