No. No Harm. As long as the plant is healthy and has AT LEAST 3 GOOD Healthy Roots left, there is no harm. I do leave more than 3 roots, but I have to give my plants a trim at least once a year. Except for about 6 Ascda. which are attached to Clay or wooden poles, all of my Vandas, Mkras. are hanging from long wire stakes. The roots grow very quickly,become thick and tangled until they reach the ground. In the first instance I would take the roots and curl them up and tie them off the ground, but after they have grown again into a tangled mess I have to trim them.
Tomorrow I will take a picture of the now cleaned up Vanda Houses, so you can see the tidied plants,
I hope others would comment as to whether I have been committing Orchidicide!!! LOL