I should add that I have been thinking in terms of Cessna-style electric flaps rather than the PA28 handbrake type.
It is worth noting that many aircraft, that are still commonly in use, pitch down when flaps are lowered and pitch up when they are raised; the PA28 Cherokees with the slab wings as opposed to later models with the extended tapered wings all do (PA28-140 and PA28-180 etc)
Take care not to introduce a rule when there isn't one.