What you propose is a new functionality. I would prefer a new name (engage_rtp_proxy) for this function and still drop the old force_rtp_proxy.
ovidiu,
it may be confusing to call the new function engage_rtp_proxy, because similar name is used in mediaproxy module for a dialog based function that tries to handle the whole dialog, but fails to address important issues, such as forking.
if the idea is not to have a dialog based thing, then function names like use_rtp_proxy/end_rtp_session would be better.
-- juha