In looking through Doug's book, "Nail Structure and Product Chemistry", I find no reference to tip blenders. Could you provide a page number?
Maybe with some products by some companies there could be some problems but not ALL of them. In my 10 years of being in the business and using a tip blender there has never been a problem or any yellowing. Experience does count for something! And yes the art of blending is a great tool to have, which I can do, but also cutting down the time to make money, provide quality service and making the client happy is important too. Not all companies are out to cheat their customers and their products are designed to help the nail tech. And using a tip blender has nothing to do with being safe or providing a safe service.
No offense intended, just voicing my opinion based on my experience. I am not a chemist, so I cannot make comments about chemicals and reactions. But if you have a page number in reference to Doug's research I would be more than happy to read it.