I never said they should be ignored. I merely stated the fact that they are quite often overlooked when a user sets up their site. It may be for the reason I stated, or even more likely it is because the average person setting up a web site using a shared hosting provider has no idea the standard exists. So, yes, it can more often than not be attributed to lack of knowledge (ignorance).
Show me. SpamAssassin et al provide many different ways for people to analyze mail. Because a rule can be written does not necessarily mean it will be employed. Nor does it mean it is a standard. Case in point, for clarification:
header Subject talks about losing pounds SUBJECT_DIET 2.527 1.621 2.084 1.466
BTW, the SpamAssassin test link is a couple releases behind. Here is the latest:
As I first stated, this is where top priority should be right now. The first question I would ask is "Are they running their own DNS server(s) and if so, who is the person responsible for set up and maintenance?"