I'm using the latest version 2.7.2 too and I'm able to see the Attendees List showing as well the "Show Expansion for Group Members", however, even if I click Yes on the "Show Date Registered" I'm not able to see the date on the frontend, which on the other hand is showed correctly on the backend Records.
As Yinyang reported... this is not a global issue. Works for him. Works fine on all of our test sites also. Got a ticket on this so we're looking into what is causing this. Will have a solution right away.
This was an issue for us also and upgrading to 2.7.2d resolved it. Works great now and the problems we saw in previous versions with scrambled fields, etc. has also been resolved. This is a great addition to the front-end as we were using a custom solution for the listing prior to this. It's also great design work on the part of DTH to provide the capability to select which columns to display, plus adding the attribute if they are back-end or front-end fields. You are getting our confidence back with the 2.7.2d release. Let's hope the mystery of the registration amount appearing above a blank page stays stable now.