I have had a rock flower and a maxi mini within 6 inches of each other for three weeks with no problems/walking. They're on different rocks, in a 12 gallon tank, no carbon/chemical filtration or protein skimmer.
I'm working on a 7.5 gallon that they'll go in together along with LPS + hopefully more nems, I'll pop back in if the whole thing blows up in my face, lol! (I will be running carbon on that tank, though.)