Ya I used to be gold and had a utopia lot, I still have it. I think at this point there isn't much sense in taking away the lot, but I could see him changing this since you are no longer paying for the privlage
Whilst there is currently no automatic process in place to reclaim additional lots if supporters stop supporting, there will be a process introduced in the near future to do this. It will likely be that after you have stopped supporting you will be contacted to choose which lot/lots you would like to keep, but if not replying to request after a specified amount of time one would automatically be unclaimed for you. If you had definite plans to become a supporter again it is likely we wouldn't claim any from you though, they would be safe until you began supporting again.