Riding in jeans with no knee guards. Your one brave man! Or should stupid be inserted? Not trying to be nasty mate, but bush bike riding you are asking for trouble. We always went out wearing the full gear, knee and elbow guards, kidney belt and body armour. This stuff had saved me on many occasions. Cept for my last ever ride which didn't end up well.
I will tell you this, take it with a grain of salt if you wish mate. We had a chick in our group a few years back get her bike licence and wanted to come out with the boys. We went camping for a weekend, she came with her bike. She though to take her bike for a quick ride around the camp site, no protection on her at all. Being the ditsy girl she was, she manage to stack at walking speed and she smashed her knee on a rock. Totally stuffing her riding desires for ever and also her career as a personal trainer.
Just putting it out there mate. Safety and protection is number 1 with this stuff.