Re: I can't get the sensor to fit
"It might be the case that the sensor was simply dropped whilst being handled, and then put on anyway, because the alternative is for the worker to own up to damaging it, and suffer the consequences - which might be punitive."
Exactly. It's cultural.
In Toyota or Sony, to name just two I know a bit about, the worker would admit to having dropped it, the sensor would be replaced properly, and the quality circle would address itself to ways of preventing sensors from being dropped and damaged.
An example: wall hung toilet bowls. These are prone to damage by being dropped. Unless you buy them from a certain German manufacturer who supplies them with the foam packing formed into an assembly jig which holds them secure and presents them to the wall at the right height.
Then there's the marine engine builder who supplies each of their engines with a beautifully shaped jig which simultaneously compresses the piston rings and slides the piston down the cylinder in a straight line, preventing ring damage. When you see that compared to the crudity of people trying to get ring compressors to line up over a piston, you appreciate real quality engineering.
I've worked for a company where the production director had to be fired to start developing a blame-free culture to get towards zero defect assembly.