There is a fine line between such measures and the preservation of the natural experience and in my opinion this line is being crossed on many occasions by parks management. You are about to enter the real world. Wet rocks are slippery. When you slip and fall it will hurt and you may also get wet.
Branches fall from gum trees, particularly on stormy days.
If they hit you on the head it will hurt. Gorges, by definition, have very steep sides often forming vertical cliffs. If you walk over the edge of a cliff it will hurt. Snow can fall at ANY time of the year in alpine areas. Snow is very cold.