I feel like I did have some workaround for that.  Or maybe I was just writing the schema in a weird way to avoid that problem.  In any case I think I'm fine with making it explicit.  Still, I think it should be possible for other custom tags beside `omap` should be interpreted with an ordering. 

It's too bad that they didn't just add a separate syntax for this.  I might have used `*` or something instead of `-` making it explicit (while support for actually preserving order could have still been left optional).