In summary (i think) the honeypot extension currently works with Contribution pages. This pull extends it for Membership and Event pages, but does not yet work with standalone Profiles. The extension developers may welcome funding to add such a feature
I believe you have found this honeypot extension. (According to the documentation this one could be used for protecting the contribution forms.)
As far as i see, it uses hooks for extending the from and validation logic. It implements the build form hook here and the validate form hook here.
If i understand you well, you want to protect the profile forms ...
Sorry for the confusion here folks, I was mixing 'profiles' with 'custom field sets'.
My membership profile contained custom membership fields and this profile wasn't available when editing or creating some specific membership types.
However, what I didn't realise was that when setting up custom membership fields you must choose which memberships you want ...