Miserlou, I don't know what you mean or what your post is trying to achieve.
If you have a conventional wing setup, meaning a main wing roughly halfway the fuselage but a little bit *behind* the center of gravity, and a smaller, tail wing at the back, that tailplane at the back produces a down force. Period. Otherwise the aircraft would be aerodynamically unstable (ie. more airspeed would force it to go down, less airspeed means up, very dangerous as this would force the aircraft, if left alone, to either overspeed into the ground or stall into the ground). As far as I can interpret all the posts below, everybody seems to agree on that (tailplane generates a downward force unless inverted), although it took a few posts to work that out.
If you have a canard-type setup, which means that you have the main wing more or less at the back of the airplane, some way behind the center of gravity, and you have a smaller wing (the canard) at the front of the airplane, far in front of the center of gravity, then the dynamic balance is completely different. Both wings will generate an "up" force but the angle of incidence of the canard is set up so that it will stall before the main wing stalls. So at a too-high angle of attack, the canard loses lift (because of the stall) and the nose pitches down, breaking the stall. OTOH - I'm not an expert on canard setups and I don't know how they become dynamically stable. I guess that the lift of the canard (due to the higher angle of incidence) increases relatively faster than the increase in lift of the main wings as the plane start to fly faster. So the aircraft pitches up and this reduces the airspeed again.
Now there's also an aircraft which has a three-wing setup. I think it's called a Pilatus or something. Probably even more complicated.
The thread so far never has touched upon the subject of stall warners at all, but the reason for stick shakers (or not) lies in the general aerodynamic effects of a stall. If the airflow over the main wing, in a small aircraft with straight (not swept wings) gets close to the stall, it separates at some point and becomes turbulent instead of smooth. This turbulent air flows over the tailplane and can be felt directly through the controls. Pilots learn to recognise these jittery controls as one of the indicators of an approaching stall. In fact, a lot of light aircraft have a slightly higher angle of incidence in the inboard sections of the wing as compared to the outboard sections. This ensures that the aerodynamic stall warning, due to the inboard section of the wing stalling, is present while the outboard sections of the wing are not yet stalled, and thus your ailerons remain effective.
In a large aircraft, with hydraulically actuated elevators, or fly-by-wire, this direct aerodynamic feedback is either dampened or completely absent, so an artificial stall warner (stick shaker) is added to simulate this effect. This is all in addition to the normal stall warners (based on a suction pipe, vane and/or AoA meter) because sometimes a tactile (feel) warning is easier noticed than an audible warning.
Large airlines also typically have swept wings for better performance at high speed. For some aerodynamic reason that was explained to me once but which I have now forgotten, the stall in these aircraft starts at the wing tips instead of wing root. So again, the burbling of air would not be felt through the controls because the tailplane does not sit in this ourboard turbulence. But a stall with a swept-wing aircraft is even more disastrous because, as the outboard areas of the wings stall first, the center of lift of the wing moves *forward* (because the wing is swept backwards and the outboard, backwards sections don't generate lift anymore). This changes the dynamic balance further: if the center of lift moves forward the aircraft pitches up, increasing the AoA and thus the stall. Possibly to a point where recovery is not possible anymore. Another reason for having very pronounced stall warnings in these types of planes.
Is all this dangerous? Not at all, as long as you understand the dynamics involved and don't let the aircraft get into a stall uninvited.
And the earth is flat. No doubt about it. Look at the horizon. Can you see a curve there? So there you go!