The "conventional wisdom" is borne out of monohulls - the techniques used in multihulls are limited and used almost exclusively off the wind.
For example, monohulls have multiple ways to violate Rule 42 upwind - rolling, pumping, bouncing - as OTW judges, we're taught to focus on the upper leech of the main and look for the "flick" caused by pumping/bouncing. You won't see that in a multihull with a fully-battened main and lots of leech tension. Without the flick, you're not propelling the boat.
On the other hand, downwind on a non-spinnaker multihull (Hobie 16) is ripe for pumping and ooching. Especially since the class rules modify RRS 42:
27 - PROPULSION
RRS 42.2 is deleted.
RRS 42.3 is deleted and replaced with:
42.3 Exceptions
(a) To initiate or maintain surfing or planing, the
crew may use sudden forward body movement,
stopping abruptly (ooching).
(b) To initiate or maintain surfing or planing, the
crew may fan any sail by pulling in and releasing
the sheet or boom or by vertical or
athwartship body movement (pumping).
(c) After a tack or gybe when the battens are
not parallel with the sail, the crew may pull
in and release the mainsheet or boom to invert
the battens.
(d) The crew may roll the boat by use of body
movement, repeated adjustment of the
sails, or steering (rocking).
(e) The crew may make repeated forceful rudder
movements to turn the boat (sculling).
(f) A boat may reduce speed by repeatedly
moving her helm.
(g) Any means of propulsion may be used to
help a person or another vessel in danger.
(h) To get clear after grounding or colliding with
another boat or object, a boat may use
force applied by the crew of either boat and
any equipment.
