Tall boots for XC are the only permitted way in North America - you cannot ride any sanctioned event without them.
Every Mid to Upper Level Eventer that I see, wear tall boots - but again, nothing else is acceptable at recognized and sanctioned events.
I grew up riding in Pony Club, and Pony Club in North America is quite strict on their traditions and regulations - and anything but tall boots are unacceptable.
You wouldn't ride at an A rated Hunter show with paddock boots and 1/2 chaps - nor should you for XC.
I understand traditions are different in different countries, but in North America, you wouldn't be caught dead at a recognized event with paddock boots and half chaps.
Traditions are traditions here, and respect for the sport is just that - respect the traditions, and stick to what is acceptable.