I have reversed with my Janomes' walking feet and never had a problem. Never even looked in the manual to check if I was 'allowed' to or not. My machines are post 2006. If you go very slowly in reverse, you can see the walking foot action in reverse. Having said all that, I have never reversed more than half an inch.
But my Pfaff has a built in stitch regulator and has certain feet that do not allow using the regulator.