Coming down the Sunday with a few pals (no tickets)

Usually at festivals you see alot of people leave the Sunday and hand out or sell their wristbands to people looking to get in, with Fontaines Headlining sunday im expecting many people to stay rather than leave

is it still likely to happen?
ive heard security is quite relaxed on the sunday so thinking of sneaking in either way, not by hopping walls or anything/literally just walking through