Justoon, you and I both know the practicality over this ... but lets look at it objectively, forget what some tree hugger wants for the tree and lets look at this.
What's the alternative?
Ladder, F that and way unsafer. In fact I fell 4m when ascending the ladder go to the top and slipped. You are not secured on the journey up and down and you cant work 360 degree view of the head. Many times you have to go back down to raise/move the ladder. Also ladders aren't always long enough.
EWP, even if you forget cost then access is an issue.
Rope over palm head and go up ... put your life onto the fronds of a palm? Risk a cut our like Recurve did and fell?
Which leaves special non invasive climbing apparatus at around $2500 to go up the trunk. Are they even available in the shops here? Nope.
Work cover is about safety, AS4373 is about tree care, and spikes win the safety argument over other methods except EWP. Besides, name me one prosecution over spiking trees.
I also have attached a copy of the wording, and the wording is
SHOULD BE AVOIDED not
shall not be used 
