Well, I think you get the picture. Boundaries can help establish order & safety. Sometimes when safety or fear is an issue, greater and stronger boundaries are established.
Sometimes we see children with autism move away from others or get under tables and chairs. Are they trying to establish boundaries? Are they trying to say - I need my space? Observe and see... when do they seem to go there and move away? It may be that the child is truly needing his/her own space to de-stress, etc. So, think about making an area just for your child - some call it "home base" where the child can go to be left alone and chill for a while. The child can learn to even set the timer to keep from staying too long.
Anyway, food for thought! Think about it!