Sadly apart from the odd hint that getting to planned destination might not be possible there's hardly a hint of scepticism or a health warning in Simon Calder's article.
Whilst there may not be a warning in the article, to get onboard and book a Wingly flight, you have to read all of their terms and conditions, which does include that there is an aspect of risk, and that if the pilot says we're not going, whether due to weather, or ANY other reason, then that decision is FINAL and the 'customer' gets their money back.
Whilst advertising an Air Taxi sort of system is completely illegal, I cannot see anything wrong with taking someone up for a sightseeing flight who wants to go. Or, even, if I have planned that I'm going to fly up to Leicester to visit family on this day at this time, I can advertise that and offer, for a contribution to the cost, the spare seat I will have. This isn't a taxi service, it's just sharing a flight, like you may share your car.
As Jonzarno says, it's no different to offering a flight on here. There is a certain contributor on this thread who has very kindly offered me a flight with them so I can continue to learn. I've told them I am a low hour PPL holder (which I am), but they have no physical proof of this, I could be a lunatic (if you're reading this, I'm not
).
I took an ex-colleague up a while ago, never really knew him outside of work, and hadn't seen him for about a year, but after I posted on Facebook that I'm going for a quick trip around the local area, and if anyone wants to join me, they can pay 50% and I'll take them up, he wanted to. I explained all that was going to happen, and that there is a chance we'd get to the airfield and I'd call it off due to bad WX. He knew this, and he still came with me. It just so happened that after about 40 minutes, some unpredictable worsening visibility caused me to make the decision to cut the flight short. He understood as he didn't want his safety put at risk.
I think most potential passengers have enough of a strong self preservation instinct to know that if their pilot says 'we're not going, it's unsafe', they will accept this without any arguing.
And, GBS, you are reminded of the main points of the T's and C's during every phase of 'booking' your flight. Charter pilots have to deal with PAX pressure because they are operating a business, and the customer has paid for a flight (often many hundreds, if not thousands, of pounds) to get to a location, like a meeting or something. A Wingly pilot does not have to do this, they say they're going somewhere, on condition of the weather being good, the A/C being serviceable etc etc, and IF someone wants to join them, then for a CONTRIBUTION (pilot not making money), then they can.