CRM-16979 Error Message "The selected profile is using a custom field which is not assigned to the %1 being configured.

When using custom fields designed for Contacts in an event registration form, the warning "The selected profile is using a custom field which is not assigned to the 'Event' being configured" occurs. This seems to refer to a mismatch between the information being collected and the event registration form, but this is not important information to the form creator, nor does it indicate what concerns the warning is really addressing. Without more detail, it could also refer to the fact that some profiles may not be appearing in the profile dropdown, but if so, this is more of a debugging or info level alert.