I don’t think it’s likely to happen in supermarket toilets or in shopping centres.
I’ve just remembered one shopping centre baby change I used a year or two ago. The baby change was locked with a radar key so I had to find a cleaner to open it for me.
It was purely a baby change, not doubled with a disabled toilet or anything, it just had a changing table, sink and bin, so I was puzzled about it being locked. It also was lit by blue uv lights rather than normal lights.
I was talking to someone about it later - apparently that particular town has a drug problem and loads of the public toilets there have been fitted with the blue lights to make it harder for junkies to inject drugs. Which also probably explains why the baby change was fitted with a radar key lock.