... if there is no semantic interconnection (HTML-wise) between the question and the form field for the answer ...

But I know, that's only another type of security by obscurity. And: yes, it is breakable.

Tschö, Auge

But in a case like a pre-made forum, that will likely be around everywhere in the same place of the forum code... so bad programmer (bot programmer author) will likely have no great problems on making that relation between the question and the place to be dropped the answer. I would like really like to believed they can't do that... but I think they probably can... so reCaptcha may be just another alternative (should the current ones implement failed), if such threat appears to brake the security.