You can't offer a .biz customer a "FOR SALE" page (with the registrar's logo), for free, then expect the customer to know that selling a .biz name is against the rules.I'm sorry, but it is the customer's responsibility to know the rules. When they enter into a legal agreement with a registrar it is in their own best interest to be fully aware of the rules, IANAL but there's no end of case law supporting this view. If you sign a contract without reading it, why should anyone feel anything but distain? The law doesn't exist to protect fools from themselves.
If in fact there are registrars offering free 'For Sale' pages I'd appreciate some hard evidence as you don't give any pointers, which one would assume could easily be done if they exist. If they do exist I would agree that that could be confusing to registrants, however you aren't too clear on whether these are pages already containing the string "For Sale" or words to that effect placed there by the registrar, or an editable page on which the registrant can place that string. If the latter, I still have no sympathy for the registrant, nor do I think the registrar should parse it looking for that string. That is getting into content control, and would be near pointless in any case as those wishing to sell their names could use "4 Sail" and endless other variations, or a "For Sale" graphic requiring that all pages be policed by reasonably sentient humans.
Feel free to disburse my cloud with some evidence, or accept my distain (although I wouldn't use such a strong term for what I think of speculators in general, for the most part they do have my sympathy). -g