There are lots of differing opinions regarding viruses in orchids.
I have spent much time not only trolling the internet about it, but also phone calls to some very prominent nurseries/collectors.
CymMV is not a highly contagious virus and is generally spread with poor plant to plant technique. I personally feel no problem whatsoever enjoying a plant that appears perfectly healthy, flowering etc until it is no longer so. I feel confident in my ability to keep it separated from my non-virused plants and my techniques in handling my collection. I am not alone in my opinion as I have been told on more than one occasion that collectors will tolerate a CymMV+ plant in their collection.
Color break virus also know as ORSV/Tobacco Mosaic is highly contagious. A splash of water can spread it. These plants also decline rather quickly. The virus ruins the blooms. Under no circumstances is this virus tolerated in a collection.
If you took the time and money to test all of your healthy plants you may be surprised.
Furthermore, it has been documented that virused plants with low viral levels can test negative, particularly the younger parts of the plant. There are theories that all plants are virused but do not manifest a positive test because the plant's immune system keeps the level too low to register a positive test. Can we ever really be sure?
So basically, you cannot make blanket statements regarding viruses in orchids....you open up a can of worms, or worse yet...viruses