I think that in @example like environment, it could happen that somebody
wants to do the alignement by himself, and so have spaces kept in some
environments. Though I have never seen it in real life.
I have never seen @item used inside @example. It doesn't make sense to me.
(I doubt it works in TeX, at least.)
I don't know (or really care :) what current makeinfo behavior is, but
my vote is to unconditionally ignore spaces after @item. Come to think
of it, it seems like spaces should be ignored after any alphabetic
command name, including @verb -- but not the non-alphabetic ones. Are
there any exceptions?
E.g., a construct such as
@emph {foobar}
should ignore the space between the @emph and the {.
Wdyt?
karl