You're right. The high setting is probably a kickstart, even if the full voltage is only applied for a very short time. It's probably more of a safegard than a necessity, though. Most fans should be able to spin up on the low setting. Perhaps inconsistancies in wall voltages is part of why they feel the need for a kickstart.
On the other hand a simple kickstart capacitor circuit would be far easier, reliable and elegant of a solution.
The fans that do:
High - Off - Low
Are probably designed with "each setting is only one click in either direction from the off position".
If you want my opinion, most fan controls are lame. A simple pushbutton control works great, it was on several fans I've owned in the past, which were mostly from the early 90s and now broken. You have off, low, medium and high. Pushing one button pops up all the other buttons. I forget the name of these switches, but I'm sure you've seen them around.
The best fan control would be a simple PWM circuit. Although more expensive to make for an AC motor, they're far more efficient than the resistive elements in most fans and offer a FAR greater range of speed control. It rapidly turns the motor on and off at the rate of the duty cycle. The faster you want it, the shorter the delay of applied voltage. The slower you want it, the longer the delay. And since all you're doing is giving the rotor a kick to keep moving, you can get your duty cycles down very low. A simple capacitor kickstart is all you need to make sure it turns on. How awesome would that be though? Be able to select any speed, any volume. We've all had a fan where medium is too much and low is not enough, or low is too much and off isn't enough.
Of course you could just use a high voltage rheostat like a light dimmer, but that is SO 20th century. Not to mention it can't achieve the low speeds of short PWM duty cycles.
Which reminds me - someday whenever I own a house, I'm going to have all LED lighting and PWM dimming. Modern solid state lighting is very efficient, moreso than fluorescant bulbs. Luxeon LEDs for example, are very, very bright and have very wide viewing angles. Not to mention them come in all colors, including very pure whites. It would save you a lot on your monthly electric build...
Bassoon, n. A brazen instrument into which a fool blows out his brains.
