You are standing with your 12-year-old son in a field with 70,000 people. A small hyperactive 53-year-old Australian with wild hair plays a storming 20-minute guitar solo in teeming rain on a podium in the centre of the crowd while his bandmates stand on stage, dry as sticks. It is the climax of a wonderful concert by AC/DC.

You feel exhilarated, delighted to have had such a joyous communal experience and proud that your boy has had a good time, as has nearly everyone in the mixed, all-ages crowd – from teens to bikers to dads with their kids.

Afterwards, you trudge along heading towards the buses. The crowd from Slane had a terrible time getting home a couple of weeks back but the word is that all that has been sorted.

You take your place in the zig-zag queue like a good responsible heavy-rock citizen and wait your turn to board a bus home… and wait… and wait… and wait. In front of you, packed bus after packed bus leaves yet the queue doesn't move. Overhead comes the whirr of departing helicopters ferrying the artists and the privileged.

An hour and a half later, the queue hasn't budged. Few stewards in sight. No police. No announcements. No news about delays. No news about anything. People are fed up. The mood changes to anger.

Suddenly, the crowd at the far end breaks through the barriers and gallops for the buses. Now the crowd at the other end follows suit.

You and your son, along with thousands of others, are cut off, trapped inside a series of steel barriers. The crowd surges forward but there is nowhere to go. Where are the stewards? A group of them stands huddled together in a far field, as though this mess is now out of their hands.

Where are the police? Who's in charge here?

Someone unhooks a barrier and slips through. Others follow suit and now it's anarchy. People skip the queues. Barriers are pushed over.

Thousands dash for the buses. Some shout abuse at the few stewards who are still around. You struggle to keep your feet. You worry about your boy. Hold on tight. Keep your feet no matter what. Trip and fall, and you will get trampled.

A lone cop tries to restore a barrier and he succeeds, but it's too late. All discipline is gone as the crowds storm the buses. Rows and arguments everywhere. Your son tells you that he is scared. You don't blame him because you are scared too. You feel powerless in the face of all this confusion, chaos and ill-feeling. You wonder how it seems to him, to any kid. Panicked, angry adults everywhere. All rules out the window. You see dads with little kids trying to find a safe way through the mass of humanity. The organisation seems to have completely fallen apart. It's a free-for-all.

Eventually, one of the bus stewards takes pity on you and flags down a packed bus. Doors hish open and you pile on. A sign on the wall notes that the bus holds 91 passengers. Here people are squished two or three to a seat and sitting on the stairs or on the floor. You don't care. Anything to get out of there. Your son makes the trip home sitting on a luggage rack. You squat on the floor beside a bunch of exhausted Germans.

You are lucky. The bus passes hordes of people desperately trying to get home.

How could things get so out of hand at such a joyous occasion?

Nobody died, so the concert must have been a success.

But for a while in the rain in Punchestown last weekend, it was touch and go. All it needed was one person to start a panic. If people had tripped over a pushed-over barrier at the peak of the crowd surge, they would have got trampled and crushed, perhaps killed.

Once when I was 10, my dad brought me to Dalymount to watch Ireland play. Afterwards, we got trapped in front of a locked exit gate. I remember elbows in my face, the smell of cigarettes and beer, belt buckles scraping my hands. Each new push crushed the breath out of me and took me further away from Dad's outstretched hand. I remember the awful feeling that my dad couldn't help me. It's a shocking thing for a child to realise that their parent is suddenly powerless.

Eventually, the gates opened and everything turned out okay, just like at Punchestown. But it doesn't take much to change a happy experience into a tragedy.

Festivals and open-air concerts are a big feature of the summertime. Oxegen is on next weekend and I hope that many thousands will have a wonderful time. I hope that there is no repeat of the chaos of Punchestown or Slane.

I love going to concerts with my kids. Usually we have a great time, despite the over-priced merchandising and the dire food.

However, after Punchestown I am going to give open-air gigs a miss. I don't trust them. I never again want to stand in a field and feel that I can't protect my kids. I don't ever want to feel like a ripped-off, tossed-away, worthless specimen of humanity just because someone somewhere took my money and then couldn't be bothered to organise the buses home.