OK as have never skied I didn't realise this was a thing.... four kids having the same instructor for 8 half days in Whistler. It is costing an arm and a leg already.... do you tip and how much? Why when they are private instructors and are paid a fortune? But I don't want to be that guest that doesn't tip. How much is reasonable or in this day and age is it a bit frowned upon (they are a professional who charge what they charge... a tip implies staff / servant and can get awks). I really don't know what is standard. Thoughts?