Darryl, I've seen this many times as well. I can explain this.
As you said, the new surfaces don't have a bacteria coating nor any coralline algae growth. This means there is nothing competing against the algae in that tank. If a person leaves the new tank in the dark (cover it) for a few weeks to age it without light he won't get this algae bloom. Some people call it NTS, I would prefer to call it Reefer Not Taking Required Steps For Prevention.
Hair algae actually requires quite a lot of nutrients to grow well. If there is hair algae there is a nutrient problem, a person can't argue that imo.
Chaeto, Caulerpa, and especially Valonia all require much less nutrients. This is why Chaeto and Caulerpa are often used for macroalgae culture for nutrient export. Valonia is too invasive for most people to want to use as it releases spores, and requires very very little nutrients to grow very well which can be problematic. Caulerpa can "go sexual" and spawn in the tank, so it is often avoided for nutrient export as well. Valonia and Caulerpa have roots so pieces that break off will sprout up elsewhere which can make them invasive. Chaeto doesn't have roots and doesn't "go sexual" so it doesn't sprout up elsewhere and is not invasive. Chaeto and Caulerpa will not survive in an ULNS provided by Zeovit or other systems, however Valonia may still persist...that is low little nutrients it requires.
Awesome tanks loaded with macroalgae in a culture tank (I prefer this word to refugium as I believe a refugium is not for nutrient export, but for zooplankton culture) are possible because there are excess nutrients in the tank. The macro culture tank provides a place to store the culture algae away from an area where it could become invasive. Chaeto is a great tool for this because as described, it is not invasive, but also because it requires less nutrients than hair algae, diatoms, cyano, dinos, etc. So Chaeto will suck up the small amount of nutrients before they can build up to a point where there are enough nutrients that other algae will start to grow. Essentially, Chaeto will out compete most other algae provided it has a good place to grow.