I have a split decision on this topic, but I really want .fixpos to change from the way it is now. Here are my two suggestions:
1-Make the bot stop ALL movement. When I'm running my Antbot, the thing that irritates me most is that collisions can still move fixed bots.
2-Make .fixpos act as a tie to the environment. This tie should be harder to break than normal ties, but perhaps allow some degree of motion, and snap it if too much tension exists.