execute_array/execute_for_fetch binding parameter types - clarification sought

I've been working on support for execute_for_fetch in DBD::ODBC. I've 
been looking around for testers and as usual the DBIx::Class users have 
come up trumps. However, a question has arisen on irc #dbi which 
although I believe I know the answer to it is not specifically mentioned 
in the DBI docs.

If I use bind_param(N, $param, {TYPE => sql_type}) the parameter is 
bound as a sql_type.

If I use execute_for_fetch I don't believe there is a way to specify the 
parameter type.

However, DBI talks about sticky types (mostly wrt bind_col) and since I 
added support for sticky types to DBD::ODBC (a few years ago) the 
following actually works:

my $s = $h->prepare(q/some sql/);
$s->bind_param(1, undef, {TYPE=>SQL_DECIMAL});
$s->execute_for_fetch($fetch_tuple_sub);

as DBD::ODBC knows you bound p1 as SQL_DECIMAL so when you call 
execute_for_fetch and it describes the parameters it knows p1 has had 
its type overridden as a SQL_DECIMAL (despite what SQLDescribeParam says 
in ODBC). It does not care you called bind_param and set p1 to undef as 
that is ignored when execute_for_fetch is called.

It appears DBIx::Class uses parameter types a lot and is looking at 
improvements using execute_for_fetch. I suggested to the DBIx::Class 
guys the sticky parameter type was probably valid (and certainly is in 
DBD::ODBC) but is this the intention of DBI?

Martin