Aside from the obvious things like guns, knives and the like, most things that appear on a 'banned items' list - like selfie sticks, fireworks and glass bottles - are completely understandable, given their potential to be used as a weapon.
But pineapples? Sure, they're spikey and it'd undoubtedly hurt if someone lobbed one at your head - but at the end of the day, they're an innocuous fruit.... right?
Not so, according to organisers of this year's Reading and Leeds festivals, who have banned pineapples from this year's festivals.
The reason that the tropical fruit has been singled out is down to Oxford band Glass Animals, who apparently have a thing for pineapples and regularly use them on stage on their current tour - in reference to a line from their song 'Pork Soda' which goes: "Pineapples are in my head." Poetry.
A spokesperson for the festivals said: "Organisers were a little concerned about hundreds of pineapples turning up on site so decided to ask fans not to bring them along. The tongue may be slightly in cheek on this one."
That may be so, but as Glass Animals drummer Joe Seward pointed out to the BBC: "Anyone who wasn't bringing a pineapple definitely is now. It's fruitist. Watermelons are fine, but not pineapples?"
They should count themselves lucky that they didn't play Dublin's Forbidden Fruit festival.