For families and couples, it can be quite a nuisance to expect an
Alioth account for every person just so that every person can be
registered.

Especially if we move beyond summit, we might want to consider
allowing multiple persons to be registered to attend a conference
from a single account. For each person, such things as dietary
preferences and t-shirt sizes would be tracked individually.

This would also have the benefit of keeping families together, which
is relevant for e.g. room allocation, child care, etc.

summit already has separate tables for authentication users and user profiles…

all we need is

  (a) a way to identify user profiles as who they are, e.g. spouse
      is already there (accompanying…),
  (b) a derived userprofile class for kids collecting the additional
      info,
  (c) the ability for a auth user to create multiple userprofiles,
      or for a userprofile to get sub-profiles attached.