For those of you who are puzzled as to why spamprotection seems broken in Userforms 3 (I was working on it) I discovered that I was too late. "Flamerohr" had already kindly commited a fix to master (tag 2.0.2) silverstripe-userforms. Upgrade your version. It might be an idea to add a note about this to the Userforms readme file.
Of course your chosen spam module might also be an issue.
See:
https://github.com/silverstripe/silverstripe-spamprotection/commit/da87f71a158905b4732aa21bc20c4833260a7dfb