No, you can't do any of those things. However, there is an enormous class of tasks for which those issues simply do not matter.
I get that people on an XML list freak out when people don't follow all the rules we think we've established. We need to find a better way to handle our freaking out than sputtering about "either stupid or poorly trained" people who "don’t have the inclination, patience or capability to fully understand your language of choice."
It makes us look bad, not them. It hurts our cause(s), and doesn't help theirs.
That attitude is exactly why I've largely given up speaking about XML to broader audiences and retreated to "markup". It doesn't carry the elitist baggage or visions of infinite complexity.