I try not too be too nanny state, But I have to agree. You won't find me under a vehicle without axle stands. A jack could easily fail or be nudged by mistake.
You can get a set of fairly decent (5t?) stands off ebay for about £30-40 delivered.
We had it drummed into us at Automobile Engineering collage, and if they had their way, you would have put ACRO's under a full car lift before going under it, but nothing drives it home like the day I was asked by a policeman knocking on the door, if I had my Keys that fitted the JCB parked round the corner, and could I use it to lift a car up?
Our village butcher closed early on a Wednesday, and had spent the afternoon working on his car while it was supported on a hydraulic bottle jack. When his wife got home from work, he was still under the car, just his feet sticking out. She gave him a gentle kick, and told him she was going in to put the kettle on and to start tea, and he should come in and get washed up. 1/2 hour later she went out to see what was taking him so long, to find he had not moved...
The trolley jack had blown the seal, and dropped the car on him at some point, killing him... worst part was, the corona, implied that it was not a very fast death, as for a while, his chest will have supported the car.
I never go under a car now without something under it, even when I have a puncture, I put the spare wheel under the car while I jack it up, and then the punctured wheel under while I finish changing it, although that is not as much help on the 4x4, as it was on the Volvo V70.
Last Christmas, Suz bought me a brand new, trolley jack, one of those flashy ones that go from super low, to super high, and made of light weight ally... First time I used it, I lifted the car up, put it on Axle stands, finished working on it, and then when I went to get the car back off the stands, the seal went. I did check to see if she had recently taken out any insurance policies on me!!:nenau Worst part was, none of my other jacks lifted anywhere near as high, so I had to risk my neck using wood under the T2 jack to get it back off the axle stands.