TICKETS – check. Phone – check. Sunglasses – check.

We were all set for a night in sunny Edinburgh watching Harry Styles perform ... or so we thought.

Only once we were en route did I remember we were permitted to bring empty water bottles with us, and fill them from water fountains in the stadium.

It was a sensible policy that reduced the risk of swooning fans dehydrating during Adore You or downing contraband shots of gin along with their Watermelon Sugar.

I kicked myself at our oversight, especially given the Deposit Return Scheme (DRS) was back in the headlines that very evening. But not to worry, I thought – we would buy bottles on arrival and take them home for future reuse.

“I have to take the lids off” explained the young woman at the kiosk apologetically after taking two bottles from the fridge.

We were confused. Did she mean she would have to take them off and ... hand them to us separately? “No, we have to keep them. That’s the policy for all the vendors in here.”

Ingenious. We were able to buy plastic bottles but there was a policy in place to specifically ensure we did not attempt to use them more than once. Is Lorna Slater aware of such madness? Do these count as single-use plastic sales? They should.

I could understand – while still disapproving – if this was about generating additional sales for the food and drink vendors, but the water fountains were still available for us to use with our lid-free bottles (essentially now rendered eccentrically shaped cups).

A hybrid of these policies is in place for the Primavera festival in Barcelona, where attendees are allowed to take in bottles of water without tops. I’m similarly struggling to find a logical explanation for that, unless the beachside location raises fears someone might try to lob plastic bottles of vodka to friends from a passing yacht.

At least, I suppose, anyone who bothers to keep hold of their bottle can reunite it with its cap once home. But what became of Murrayfield’s withheld caps?

In some respects, other systems in operation in Scotland manage to be even worse, with festivals and venues “green-washing” while apparently giving no thought whatsoever to practicalities or even ethics.

The crusade against single-use plastic has provided opportunities for firms that supply reusable cups, but for the consumer, these too often end up feeling like a con.

It makes sense to charge a £1 “deposit” for a cup, in order to incentivise the customer to bring it back to the bar when they want a second drink rather than dropping it on the floor or cramming it into a bin.

But in practice, the £1 is more like a tax, because how many of those exiting the event either remember to return their cup or can justify queuing up to reclaim £1 when they have their evening to continue, a train to catch, a babysitter to relieve of their duties?

In some venues, gig-goers can end the night with a few minutes of cup-collection and receive £1 for each one – a win-win for those with the time and inclination and for the venue, which then has less cleaning up to do.

The principle here is the same as that of the Scottish Government’s much-discussed national DRS: once the necessary barcodes are introduced, it doesn’t matter who returns the can or bottle – they will receive the 20p deposit. The empty item will be worth 20p as long as the code can be scanned, thus providing a cash incentive for litter collection.

But if you’ve attended a venue with its own privately run scheme in place you’ll find there are rules in place to ensure they keep as many of those pounds as possible in their tills, such as arbitrary limits on the number that can be returned per person or, in the case of one Glasgow theatre, demands that patrons debase themselves by providing proof of purchase.

There’s surely nothing more likely to turn people against sensible environmental schemes than turning them into profit-making little scams.

The firm Green Goblet boasts that it is “the UK’s leading producer and supplier of reusable cups, coffee cups and food-ware”, and claims to be “on a mission to save the planet one reusable cup at a time”.

But scroll down past the environmental boasts on its website and you’ll see its selling point is providing custom-printed souvenir cups for the likes of festival-goers and wedding guests to take home with them. How many homes are crying out for more plastic cups, or more plastic full stop? The concept of a souvenir cup could hardly be less sustainable.

Sure, a repeat festival-goer might take their souvenirs back year after year, but I doubt it. No thought is given to the practicalities of tramping around a festival site constantly carrying a sticky pint cup.

Adding a small hole near the top of a slightly larger receptacle would permit a carabiner to be added then clipped to a belt loop or bag. That none of the reusable cup rackets have thought to do this perhaps tells you everything you need to know about their business models.

While the DRS debacle rumbles on, Circular Economy Minister Lorna Slater has the chance to grab two quick wins here: ensure bottles keep their caps, and that venues and cup suppliers don’t chug down the majority of the dubious “deposits”.