TFL are doing some platform work at Stepney Green station at the minute which makes for an interesting nudging case study in progress. It's all about getting people to stand back from the platform edge without knowing it.
A bit of the platform has no marks next to the platform edge, people go really close as a result.
Another bit has the yellow line, people go less close.
And the newest bit has yellow line plus texture surface stuff. People stay the furthest back of all.
All pretty much without even knowing it.