andydallas , riding is indeed good for you. This thread is about the potential dangers to watch out for when riding if you are prescribed blood thinners. Most of the times, as you said, there are no risks. But if you fall, there is a "potential" for both external and internal bleeding. External bleeding is easy to spot and can be controlled for the most part. The issue could be with internal bleeding which is not easy to spot. Hematomas or bleeding just under the surface can also be easily identified (though not easily controlled). Any internal bleeding due to blunt force trauma (a fall from about 3' is more than enough) is not so easy to identify and can be fatal.

At the end of the day, it's a risk-benefit analysis. So long as one is taking the proper precautions, there is no rule against any activity.