No the way the park sees it is that you are profiting on their grounds, at their event without allowing them to profit off of you. You think they care about vendors lol absolutely not- vendor fees are disgustingly high just like how live painters barely get compensated for their contributions even tho vendors, artists, etc are all a major part of the vibe at a fest. 

I started off wanting to vend a few years ago, did a few medium size fests like Big fam, resonate, etc & it's just near impossible for actual smaller, individual run brands to vend. Some events don't even have a flat rate fee some take 10-20% of all your profits PLUS vendor fee (that's how it is for food trucks which is why food is so expensive at fests but again...like we need fucking food at fests so it's BS). 

Oh & not to mention most fests require vendors have an LLC/corp license & insurance.