Well I think, and I'm saying this with a "...but I stayed at a Holiday Inn Express last night..." mindset, they're looking for a happy flow spot they can park it and get all the food blown towards them. If they're wandering that much it might mean they really aren't happy anywhere in your tank. Unfortunately people get this mindset of a place they want their anemone to stay in a particular place and they really don't.
Granted I'm by no means an expert only having successfully kept my current anemone for 3-4 years, I've killed a few anemone in the past starting with the ugly brown bubble tips, green variants, even one of rose variants as well. My current ones, I guess I got lucky for the tank they were in that the big rock they were on had plenty of crevices and the flow was perfect for them that they didn't wander, and subsequent clones that split off stayed right on that rock (one new clone did wander but it eventually came right back to the rock). They got a good light source, the flow is there to bring food right by/through their tentacles and I get no wandering.
So its not so much they require a high flow, its that their food source (not light!) is brought to them via flow, and if they can't get what they feel is adequate they go searching for higher flow. More likely than use a foam cover on your powerheads you'd be better off pointing them in a different direction.
