It's just faux pas. Possible fines. It seems the general consensus is natural is ok, structures are not.
Although a built a natural gap jump, laminated signs warning and chicken line. Still got taken down, even though blue Spade etc exists [emoji1745]
I found that I could replicate the creak by back brake on, front wheel up into 12/6 position above rear and bounce on the back wheel. (Fox 36).
It went back under warranty and was 'serviced'. Creak stopped for about 3 months then returned.
This ^^^
I've had renthal pretty much my whole MTB journey. I changed to 35mm diameter at the same time as other upgrades so couldn't apportion the stiffness to one thing.
I've since changed to enve m6 and noticed big improvement, so yeah, it was the bars all along.