I think the doctor comparison came from one of my earlier posts. It was trying to figure out if ski instructors should be viewed as professionals, some one who is dedicated to the craft and takes it upon themselves to advance their skill in the craft, such as level 2/3 PSIA. Or are ski instructors just ski bums with nice jackets who use their jobs on the mountain to have more access but shouldn't try to live off the ski instructing gig. Then when discussing expected tips, the comparison to a waiter came up, because it's common knowledge that most wait staff make below hourly wage and their pay really depends on tips. I think it's a very dissimilar comparison to compare a waiter to an instructor. Instructors require much more skill and dedication to the craft than waiters, and apparently it's not common knowledge that ski instructors need tips to survive.
I think most agree that instructors are more similar to a doctor (per the definition of professional) vs waiters and as such, the underlying perception exists that the instructors are well paid from the high cost of the lesson. We all know that isn't the case, and think it's wrong, but barring a nationwide strike, there's not much we can do about it, since there will always be a dumb college kid who just wants to ski for free (like I was) and will accept working for peanuts for the privates of access to the mountain.
Even though I think it's wrong that instructors don't get much of the take from the house, I'll still tip as a habit, especially if the instruction was strong, because I know it's greatly appreciated and darn near necessary.
All of this ^^^.
Although I realize the argument is pointless because no one is changing anyone else's mind on this topic (except perhaps informing the few people who read this thread wondering about the acceptability of tipping ski instructors in North America), I would like to reiterate - as others have - that ski instructors are not in a position to strike or negotiate with their employers. So, it's not as though we are choosing not to act in a situation that we could remedy. The choice is a bit different here. Yes, we have made a choice to work in the ski industry in North America. Yes, we know the pay is crap. Yes, we know that much of the cost of being a professional in the industry will fall on our shoulders (yes, primroz, many of us do come out at a loss at the end of the season). So, are we asking that our guests to solve our problems? No, we don't EXPECT a tip. No, we don't expect guests to break the bank in order to throw us an extra couple of dollars. HOWEVER, since we work in North America where it is acceptable (and customary) to tip service professionals, we are grateful whenever we get tips. It's a pleasant surprise when guests choose to recognize their appreciation of good service.
Primroz, you make the point that it's not an issue for you because you live where tipping isn't customary. So, great. It's not your concern. Why, then, do you get so indignant about the concept that someone might consider tipping appropriate (despite the amount they are paying for a lesson)? Also, if you travel to a country where tipping is appropriate, do you still refuse to tip (I'm not even talking ski instructors at this point)? No "when in Rome" approach for you, I take it?