They can file and be granted a patent on your work against your will. The system specifically accounts for companies that need to file a patent on the work of a

They can file and be granted a patent on your work against your will. The system specifically accounts for companies that need to file a patent on the work of a "non-cooperating inventor". As an employee, your refusal will probably get you fired (since you probably agreed to cooperate with patents in your contract) and burn bridges, and all it does is force them to spend a few extra hours on paperwork. A previous employer wanted to patent some of my work, and I tried to use this as leverage to get them to implement something like Twitter's "Innovator's Patent Agreement", Google's "Open Patent Non-Assertion Pledge", or Paul Graham's "Patent Pledge" - only to find out that I didn't really have any leverage. I at least did manage to get it discussed, but ultimately it was rejected. This was a factor (though a minor one) in my decision to leave there.