Is there a way to block files, coding, etc. from being copied when giving a new programmer ftp access to do research prior to submitting a quote?
If you block files from being copied then the programmer's research isn't going to be a thorough as it could be with full access and you will end up with a poorer quote as a result.
This may just cost you time if the job takes longer, but will probably cost you money as well.
You have to trust the programmer. If you show trust and good will you will get trust and good will in return. Good contract programmers aren't going to rip you off, they need their good name to be able to work.