I put my spare tunes in a sock before they go in the saddlebag. For that reason.
It's in a plastic bag at the moment. The ones for my road bike are in a very convenient material type bag that neatly fits two in it. I've not needed the tube for the XTC ever since I last failed to top the sealant up at the NSW champs back in 2014 or 2015 and prior to that when I had the Racing Ralphs (because they sucked) so it's been a good run.
Thinking about it, I did use the spare at the NSW champs but both times with the RRs, they had holes in them.