Lollapalooza used to be pretty lax in terms of music festivals. Once upon a time, they permitted sealed water bottles and full backpacks, which is a real eyebrow raiser for those who are used to the strict terms at EDC or Coachella. The security changes came in 2018 after the mass shooting at a music festival from Mandalay Bay Hotel. While every music festival bolstered their teams in response, Lollapalooza had a little extra motivation because the shooter in the Vegas attack also had two rooms at a hotel on Michigan Avenue during Lollapalooza… he just never showed up.
Camping festivals are a whole different ball game from a day festival. And of course, a good long day festival kicks our asses back to fifth grade anyways. The extra effort of packing before a camping festival is enough to wear you out before you even pull up to the gates with a car full of camping gear, and a friend or two shoved against a window with a 50 pound cooler, a 30 rack, and a gallon of Vodka in their lap.
While some of these may not be considered an ~essential~ for you, these are common items noted during a "SHIT... you know what I forgot to bring?" moment. Luckily, there's enough PLUR going around to lend you a piece of gum when you ask some smiley strangers.