Yes,
Yes it is possible to have negative interest
If you want (and feel energetic) could I suggest you head to Cradle Mountain for the night, do the walk round the lake, feed the pademelons etc and we can meet you there on the way through?
We won't have the time to do the lake walk, but it's definitely worth doing if you haven't done it before, and it's worth us going via there for Gary to take some photos.