If you have determined power, you cannot currently decline the free movement. I reported this bug over a week ago, had to abandon one game because of it and am about to have to abandon another. I can't believe the game could be left in a broken state for so long as this must surely be affecting a lot of games. Relevant bug is here in case anyone wants to upvote it:
https://boardgamearena.com/bug?id=201914
https://boardgamearena.com/bug?id=201914