Network Rail and the variable

I felt lazy at my destination station yesterday and tried to go up in the lift.
I had never seen it so full; but there was room.
"Doors closing," said the lift. The doors did not close
After a while I said: "This is an odd lift; can you press the button again?"
A woman behind me said: "I keep pressing it."
A second woman said to me: "It's you; you're in the way, stopping the doors closing."
I answered that I was nowhere near the doors.
The doors did not close.
I wonder how long they would have stayed there...
I said: "Maybe it thinks we are too heavy with me." I left the lift.
The doors began to close.
"There you are," said my accuser.
"It was weight, not blocking," I said.
"It's the same thing," she said, certain as a believer, as the doors closed and she ascended to the short-term heaven of her choice.

Now, someone programmed that lift at design stage. They set it up so that when the combined weight of passengers exceeds n kilos, it stops. They equipped the lift with playback of recorded voice. They did not bother to equip it with a voice saying "passengers too heavy"; no, they just left them to do discovery learning.
A colleague of mine who teaches Computer Science in H.E. was moaning a while back that many students who claim to be able to program can't handle variables at all; and don't all seem to get the point. That's a bit of a limitation.
It would explain why, when I log in at the wifi cafe, it throws away my browser's startup url in order to tell me who I am in order to ask me who i am in order to welcome me... but doesn't give the browser back the start up url.
That would take a variable.
The British Library wifi does, though I find its constant inquiry to check I am still who I say I am a little bit dire. St Pancras wifi does. The Cloud / Caffe Nero does not.
This was, of course, a Network Rail lift.