Actually, the EQM info does not appear on the receipt at all (at least on the CO generated PDF eTicket receipt or the email). That being said, the text you refer to (re codeshare EQMs) is at the bottom of the reservation page and is not particularly obvious. In addition, the way CO presents the EQM earnings info is basically:

"You'll get xxx miles, and 100% are elite qualifying miles*
....
*... elite qualifying miles are not included in the total miles shown. The miles accrued on codeshare flights are based on the operating carrier and their equivalent fare class".

Ignoring the self-contradiction ("you'll get X" and "we don't tell you what you'll get"), it would be nice to get the information necessary to determine that the 100% EQM earning is false, but, AFAIK, CO does not provide the information necessary to determine equivalent fare class... so to most people the text is equivalent to "you'll get 100% EQMs, but we don't tell you how many EQMs you will get (you'll find out after it's too late)".

If it's too hard to accurately display RDM and EQM earnings for codeshare flights, then CO should simply not list the info.