I've seen it happen too often. A class is slated as intermediate, but a beginner will show up. Then the teacher spends the rest of class trying to balance the difficulty in order not to scare off the newbie, but keep the regulars satisfied. It's a fine line. I dislike having to turn people away from a class. In fact, I don't think I've ever done it before. But maybe I should have? Hmm...
I've gone 3 years teaching in the same studio at various levels. Most classes are all levels which allow everyone to take it at their own pace, but I do teach a few intermediate. And these should very well be reaching the advanced level since so many of my regulars have been with me awhile. However, I do find that people who aren't practicing regularly, or are new to yoga have been showing up to the higher level classes anyway. So over the summer I started teaching one workshop a month, and they have been geared towards the advanced crowd in order to teach them asanas that they can choose to take deeper in class, despite the level. Unfortunately it's been the summer and many people are away. So, I hope to continue offering these in the coming season. Until then, and in general, however...I have an answer to this dilemma.
Yoga is about developing your own rhythm. It's about knowing whether or not to push your edge or pull out. It's about discovering your strengths and weaknesses both mentally and physically. I move in my own practice through cycles. Some weeks I'm exhausted and I do a basic hatha or vinyasa practice. Some days I'm ready for an intense ashtanga series. Other days I need to leave out inversions altogether, and spend most of the time in my hips or in savasana. :) I don't see myself busting out any attitude with people and sending 'em packing just because they showed up to my intermediate class but are more on the beginner side. That's just not me. I want everyone to find their yoga. So I simply try to honor the level and announce at the beginning that it will remain intermediate, but everyone needs to take it at their own pace. I encourage everyone to take their own pace in class (and in life) as a daily mantra. So it's truly up to you. If you want a guaranteed sweaty, advanced asana practice...maybe it's time to take a break from your norm and check out a hot vinyasa or ashtanga studio a few times a week. Everyone needs to grow. All you can do is keep growing and educating yourself on alignment, the poses, the philosophy...whatever will help you find your flow. Then, all you have to do is show up to any class, and be able to judge for yourself where you need to be on your mat that day. Hope that makes sense? I'm open to discussion. Just love yourself, be yourself, and breathe. One class at a time.