Yes, the picture does not look much like Meraki, correct. The Meraki MR part is just too simple (MR84, MR72, MR33, … you all know them! 🙂). The real challenge is to split the internet-traffic in a redundant way to all those USB-LTE-sticks properly, as there is no other internet connectivity available at the festival location.
Next time the festival is held (some virus may stop us this year), we may implement some custom client tracking.