So that attendees can verify the information that the system has on file for them, there should be a mechanism for presenting basic user information (e.g. profile values) when uc_signup_attendees_form_profiles calls theme('uc_signup_has_account').

This would allow site admins to create theme overrides that, for example, would allow an attendee to correct outdated registration information before completing registration, or confirm that they are registering the person they intended.

I believe this can be done by adding $account as an optional parameter to theme_uc_signup_has_account, and have uc_signup_attendees_form_profiles pass that value.

It is only a change to 3 lines of code I haven't made a patch, but I can do so if you like.
Thanks!