I read a lot about honeypots techniques to prevent spam but most of articles I've seen seem to be old. So I was wondering if nowadays, with all this smart bots, the fact of simply hiding a field with CSS can block them. Do the bots understand that a field is not shown and they should let it as it is ? And also, do they understand that a field is required or not ?
In others words : how effective is the honeypot technique ?