You'd be able to exit the process if it's not a good fit using this method too. Perhaps even during an initial call before there's any type of contract mentioned.
Going for interviews while you're currently employed is also in addition to your job. It's just you're doing "real world" things in the contract based interview instead of answering technical questions or whiteboarding implementations.
- I will probably exit an interview process in an hour if the company isn’t a good fit
- We’re not talking about normal employment here. This is in addition to my job.