Your bags may be searched on the way in to the festival and banned items will be confiscated.
Each festival will have their own list of banned items but in general terms don’t take anything that could be used as a weapon such as kitchen knives, axes, saws, claw hammers and so on.
They could have perfectly legitimate uses in your camp site, but in the wrong hands it could get nasty.
Most festivals insist on no glass being brought onto site so decant your booze and other liquids into non-glass containers before you get there.
Leave pets at home to keep them safe and to prevent you from being evicted.
Fireworks, flammable things and those paper Chinese lanterns. Fires are deadly. Burns are a nightmare. A hot dry camp site is an inferno waiting to happen so please, please be careful with fire.
The lanterns look amazing, lighting up the sky at night, but local farmers hate them. Their cows eat the bits that fall from the sky and it’s expensive and tricky to remove things from inside a cow, not to mention the suffering experienced. Don’t bring them.
Keep it legal!
Don’t take anything illegal. This includes drugs. The law is still the law, even at a festival!