Festival running orders look like a series of frustrating collisions from the outside. They are the output of a scheduling problem with more constraints than an attendee can see.
Billing is contractual, not editorial
An act's position is negotiated when they are booked, and agreements specify how prominently they appear and roughly when they play.
Once several such commitments exist, large parts of the schedule are fixed before anyone considers how the day flows.
This is why an act can appear at a time that seems mismatched to their draw, since the slot reflects an agreement made months earlier.
Changeovers set the minimum gaps
Between performances, equipment is cleared, replaced and checked, and the time required depends on the size of the production involved.
Large acts with substantial staging need long changeovers, which forces gaps that cannot be shortened without risking a delayed start.
Stages with rolling risers can move faster, but that infrastructure is expensive and typically only used on the largest stages.
Similar acts are separated deliberately
Organisers avoid placing acts with overlapping audiences at the same time where possible, because it splits a crowd and leaves both stages looking empty.
The reverse technique is also used, spacing complementary acts so that a crowd moves predictably between stages rather than all at once.
Crowd movement is a safety matter as much as an experience one, and site management has real influence over the running order.
Some constraints come from outside the site
Licences frequently impose a hard finish time, and noise conditions can restrict volume at certain hours, which shapes what can be scheduled late.
Acts playing several festivals in a region are travelling between them, and their availability may be limited to a particular part of a particular day.
These external factors are invisible to attendees but frequently explain a slot that otherwise makes no sense.
Clashes are a consequence, not a choice
A festival with many stages running simultaneously will always place things people want to see against each other, since the alternative is a shorter line-up.
Organisers minimise the worst collisions and accept the rest, which is why the schedule usually protects the biggest overlaps and not the smaller ones.
Late changes make this worse, since a withdrawal reshuffles a stage and the replacement inherits whatever slot remains rather than an ideal one.