James Kilfiger writes:

 > On another matter, how will collection instances be used? Will
 > environments select a collection.  Would it be useful if \begin{myenv}
 > implictly called \UseCollection{myenv}.  You could use this to prohibit
 > sectional headings in floats, or \item outside of lists.  Would this be
 > within the expected use of collections.

 must confess we don't know that yet. we don't know eve if collection
instances are such a good idea in the first place. it is something
that will sort itself out probably pretty soon if we have played
around a bit with them.

i personally think that envs setting the collection instances is not
the way to go. when i played around with ists i tried doing this but
it didn't felt right.

as i said i don't know