There are so many types of yoga - from powerful Ashtanga series and Bikram yoga with precise positions in a precise order with precise timing to other styles with more freedom in the poses. I teach "Nutmeg" yoga. My nickname is Nutmeg (Meg for Margaret, Nut for the good crazy!). I've trained and been exposed to a number of styles and teach a freestyle with technique combined kind of class - therefore Nutmeg yoga. If you ever take training from different yogis, most believe their style and their way of executing a pose is the right way - but I believe they are all right. You don't have to follow all of the "rules" to have a successful practice.
There are other places I believe rules could be broken or bent a little. For example, at the grocery store today. I was behind a friendly woman in the express check-out lane. She admired the roses I carried in my arms and delightedly I let her know they were only $8 a dozen (20% off any size bouquet). She asked the cashier if she would ring her up a dozen and she would run back and get them. The cashier told her she couldn't. The disappointed woman exclaimed, "I guess it wasn't meant to be". I asked the cashier why she couldn't have rung up the flowers for the woman using her scanner on one of my bunches. She went into an explanation on inventory and what if the woman didn't get the exact same kind and then they would order more of the wrong one and ... I'm thinking - you missed out on making one woman's day and a sale - because of a silly rule. Sometimes the Rules Are Meant to be Broken!