At best it's unsafe, and is probably outside of what they ought to be attempting, especially if they've never done it before. In no other area of life would we consider it a good idea for unskilled people to lift 2000lbs on a spindly device while 80,000lb trucks go by 6 feet away at 75mph.
I pulled over on the Interstate the other day and couldn't believe how dangerous it seemed. I had forgotten. I thought then, man... glad I'm not changing a drivers side flat.
33 years driving all of the city on regular streets and Interstate for a living and a good 10+ of basic driving before that... 1 blowout.
Many tread nails that I actually drove on for days. One sorta sidewall nail that went fast but I could probably have plugged it / aired it, and limped to safer place if not a service station... and that was in my driveway.
I am seriously considering an XJack ( for driving on beach ). It just seems like the safest-easiest and could assist in using the bottle jack so it gets positioned properly and only jacked on for an inch or two.
Think of the stuff you could store in a giant doughnut container that fits where the spare is located. I dove a taco from 75K to 255K with the spare hanging under there and never used it except in my driveway when I swapped out a partial flat due to nail so I could drop that off at station.
It's a tough call... worried about your battery going? Many safe options for that from a dual setup to a simple Cig. Lighter plugin.
Tires are the one things that are constantly ( well on the highway at least ) in contact with the potential cause of failure.
Again driving all that I do, I think I've seen 2 maybe three people changing tires and that often ends up with some sort oversight. LEO, Traffic Safety Vehicle, etc..
the only real reason I would keep a spare is if I do pick up a nail or something.. I can at least make it to somewhere safe, swap it out, and get on with what I was doing if need be. sometimes you just don;t have the time to fix a flat right then and there. so it's good for that. But unless the Interstate had a really wide shoulder, I wouldn't want to do it... and if you end up in the grass for safety, you are going to need some sort of solid base, chocks, and sorts of other stuff. that's where a cell phone or Toyoto's $10 a month SOS program comes in.