@indigomoth - As long as you are relatively active you aren't at that much risk of developing a clot. Doctors have to be super careful about that sort of thing, so they don't get sued.
That being said, getting a clot in your leg is very dangerous, as it says in the article. If you feel your leg grow hot and swollen without being injured, you should get yourself to hospital right away.
That goes for other people at risk as well, like those with varicose veins and so forth.
The more quickly you get the clot removed, the less likely it will shift to your lungs or your brain.